herokuにpushしようとするとエラーになる

Question

git push heroku masterで以下のエラーが発生してしまいます。フェッチとマージは試しましたがエラーのままです。原因が分からず躓いています。ご教授頂けたらと思います。
remote: -----> Building on the Heroku-20 stack
remote: ! Warning: Multiple default buildpacks reported the ability to handle this app. The first buildpack in the list below will be used.
remote: Detected buildpacks: Ruby,Node.js
remote: See https://devcenter.heroku.com/articles/buildpacks#buildpack-detect-order
remote: -----> Ruby app detected
remote: -----> Installing bundler 1.17.3
remote: -----> Removing BUNDLED WITH version in the Gemfile.lock
remote: -----> Compiling Ruby/Rails
remote: -----> Using Ruby version: ruby-2.6.6
remote: -----> Installing dependencies using bundler 1.17.3
remote: Running: BUNDLE_WITHOUT='development:test' BUNDLE_PATH=vendor/bundle BUNDLE_BIN=vendor/bundle/bin BUNDLE_DEPLOYMENT=1 BUNDLE_GLOBAL_PATH_APPENDS_RUBY_SCOPE=1 bundle install -j4
remote: The dependency tzinfo-data (>= 0) will be unused by any of the platforms Bundler is installing for. Bundler is installing for ruby but the dependency is only for x86-mingw32, x86-mswin32, x64-mingw32, java. To add those platforms to the bundle, run bundle lock --add-platform x86-mingw32 x86-mswin32 x64-mingw32 java.
remote: Fetching gem metadata from https://rubygems.org/............
remote: Fetching rake 12.3.3
remote: Installing rake 12.3.3
remote: Fetching concurrent-ruby 1.1.8
remote: Fetching minitest 5.14.3
remote: Fetching thread_safe 0.3.6
remote: Installing minitest 5.14.3
remote: Installing thread_safe 0.3.6
remote: Installing concurrent-ruby 1.1.8
remote: Fetching zeitwerk 2.4.2
remote: Installing zeitwerk 2.4.2
remote: Fetching builder 3.2.4
remote: Fetching erubi 1.10.0
remote: Installing erubi 1.10.0
remote: Installing builder 3.2.4
remote: Fetching mini_portile2 2.5.0
remote: Installing mini_portile2 2.5.0
remote: Fetching racc 1.5.2
remote: Fetching crass 1.0.6
remote: Installing crass 1.0.6
remote: Installing racc 1.5.2 with native extensions
remote: Fetching rack 2.2.3
remote: Fetching nio4r 2.5.5
remote: Installing nio4r 2.5.5 with native extensions
remote: Installing rack 2.2.3
remote: Fetching websocket-extensions 0.1.5
remote: Installing websocket-extensions 0.1.5
remote: Fetching mimemagic 0.3.5
remote: Installing mimemagic 0.3.5
remote: Fetching mini_mime 1.0.2
remote: Installing mini_mime 1.0.2
remote: Fetching msgpack 1.4.2
remote: Installing msgpack 1.4.2 with native extensions
remote: Using bundler 1.17.3
remote: Fetching ffi 1.14.2
remote: Installing ffi 1.14.2 with native extensions
remote: Fetching method_source 1.0.0
remote: Installing method_source 1.0.0
remote: Fetching pg 1.1.4
remote: Installing pg 1.1.4 with native extensions
remote: Fetching thor 1.1.0
remote: Installing thor 1.1.0
remote: Fetching rb-fsevent 0.10.4
remote: Installing rb-fsevent 0.10.4
remote: Fetching tilt 2.0.10
remote: Installing tilt 2.0.10
remote: Fetching turbolinks-source 5.2.0
remote: Installing turbolinks-source 5.2.0
remote: Fetching tzinfo 1.2.9
remote: Installing tzinfo 1.2.9
remote: Fetching i18n 1.8.9
remote: Installing i18n 1.8.9
remote: Fetching rack-test 1.1.0
remote: Installing rack-test 1.1.0
remote: Fetching rack-proxy 0.6.5
remote: Installing rack-proxy 0.6.5
remote: Fetching sprockets 3.7.2
remote: Installing sprockets 3.7.2
remote: Fetching websocket-driver 0.7.3
remote: Installing websocket-driver 0.7.3 with native extensions
remote: Fetching marcel 0.3.3
remote: Installing marcel 0.3.3
remote: Fetching mail 2.7.1
remote: Installing mail 2.7.1
remote: Fetching puma 4.3.6
remote: Installing puma 4.3.6 with native extensions
remote: Fetching nokogiri 1.11.1 (x86_64-linux)
remote: Installing nokogiri 1.11.1 (x86_64-linux)
remote: Fetching bootsnap 1.4.5
remote: Installing bootsnap 1.4.5 with native extensions
remote: Fetching turbolinks 5.2.0
remote: Installing turbolinks 5.2.0
remote: Fetching activesupport 6.0.3
remote: Installing activesupport 6.0.3
remote: Fetching rb-inotify 0.10.1
remote: Installing rb-inotify 0.10.1
remote: Fetching loofah 2.9.0
remote: Installing loofah 2.9.0
remote: Fetching rails-dom-testing 2.0.3
remote: Installing rails-dom-testing 2.0.3
remote: Fetching globalid 0.4.2
remote: Installing globalid 0.4.2
remote: Fetching activemodel 6.0.3
remote: Installing activemodel 6.0.3
remote: Fetching jbuilder 2.9.1
remote: Installing jbuilder 2.9.1
remote: Fetching sass-listen 4.0.0
remote: Installing sass-listen 4.0.0
remote: Fetching rails-html-sanitizer 1.3.0
remote: Installing rails-html-sanitizer 1.3.0
remote: Fetching activejob 6.0.3
remote: Installing activejob 6.0.3
remote: Fetching activerecord 6.0.3
remote: Installing activerecord 6.0.3
remote: Fetching sass 3.7.4
remote: Installing sass 3.7.4
remote: Fetching actionview 6.0.3
remote: Installing actionview 6.0.3
remote: Fetching actionpack 6.0.3
remote: Installing actionpack 6.0.3
remote: Fetching actioncable 6.0.3
remote: Installing actioncable 6.0.3
remote: Fetching activestorage 6.0.3
remote: Installing activestorage 6.0.3
remote: Fetching actionmailer 6.0.3
remote: Installing actionmailer 6.0.3
remote: Fetching railties 6.0.3
remote: Installing railties 6.0.3
remote: Fetching sprockets-rails 3.2.2
remote: Installing sprockets-rails 3.2.2
remote: Fetching actionmailbox 6.0.3
remote: Installing actionmailbox 6.0.3
remote: Fetching actiontext 6.0.3
remote: Installing actiontext 6.0.3
remote: Fetching webpacker 4.0.7
remote: Installing webpacker 4.0.7
remote: Fetching sass-rails 5.1.0
remote: Installing sass-rails 5.1.0
remote: Fetching rails 6.0.3
remote: Installing rails 6.0.3
remote: Bundle complete! 18 Gemfile dependencies, 60 gems now installed.
remote: Gems in the groups development and test were not installed.
remote: Bundled gems are installed into ./vendor/bundle
remote: Post-install message from sass:
remote:
remote: Ruby Sass has reached end-of-life and should no longer be used.
remote:
remote: * If you use Sass as a command-line tool, we recommend using Dart Sass, the new
remote: primary implementation: https://sass-lang.com/install
remote:
remote: * If you use Sass as a plug-in for a Ruby web framework, we recommend using the
remote: sassc gem: https://github.com/sass/sassc-ruby#readme
remote:
remote: * For more details, please refer to the Sass blog:
remote: https://sass-lang.com/blog/posts/7828841
remote:
remote: Bundle completed (35.83s)
remote: Cleaning up the bundler cache.
remote: -----> Installing node-v12.16.2-linux-x64
remote: -----> Installing yarn-v1.22.4
remote: -----> Detecting rake tasks
remote: -----> Preparing app for Rails asset pipeline
remote: Running: rake assets:precompile
remote: yarn install v1.22.4
remote: info No lockfile found.
remote: [1/4] Resolving packages...
remote: [2/4] Fetching packages...
remote: [3/4] Linking dependencies...
remote: [4/4] Building fresh packages...
remote: Done in 1.03s.
remote: I, [2021-02-14T03:29:28.943208 #1069] INFO -- : Writing /tmp/build_b0187f0c/public/assets/application-e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855.css
remote: I, [2021-02-14T03:29:28.944018 #1069] INFO -- : Writing /tmp/build_b0187f0c/public/assets/application-e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855.css.gz
remote: Compiling…
remote: Compilation failed:
remote: error Command "webpack" not found.
remote:
remote: yarn run v1.22.4
remote: info Visit https://yarnpkg.com/en/docs/cli/run for documentation about this command.
remote:
remote:
remote: !
remote: ! Precompiling assets failed.
remote: !
remote: ! Push rejected, failed to compile Ruby app.
remote:
remote: ! Push failed
remote: !
remote: ! ## Warning - The same version of this code has already been built: 02b95d28c5c6219116a9ca798cd6fa95f4400fd8
remote: !
remote: ! We have detected that you have triggered a build from source code with version 02b95d28c5c6219116a9ca798cd6fa95f4400fd8
remote: ! at least twice. One common cause of this behavior is attempting to deploy code from a different branch.
remote: !
remote: ! If you are developing on a branch and deploying via git you must run:
remote: !
remote: ! git push heroku <branchname>:main
remote: !
remote: ! This article goes into details on the behavior:
remote: ! https://devcenter.heroku.com/articles/duplicate-build-version
remote:
remote: Verifying deploy...
remote:
remote: ! Push rejected to aqueous-wave-27337.
remote:
To https://git.heroku.com/aqueous-wave-27337.git
! [remote rejected] master -> master (pre-receive hook declined)
error: failed to push some refs to 'https://git.heroku.com/aqueous-wave-27337.git'