Rails6でBootstrap導入後、Herokuへデプロイができない

前提・実現したいこと

Ruby(Ruby on Rails)でレビューサイトを作っています。
Bootstrapを導入した後、Herokuにデプロイしたいのですが、
下記のエラーが発生しました。
Bootstrap導入前はHerokuへ正常にデプロイできておりました。

（環境）
・ruby 2.6.5
・Rails 6.0.2.2
・Windows　10

発生している問題・エラーメッセージ

remote:　　　Compiling...
remote: Compilation failed:
remote: ModuleNotFoundError: Module not found: Error: Can't resolve 'bootstrap-sprockets' in '/tmp/build_e08a0db1d7b9eb92bbc6b8aacfb53c4a/app/javascript/packs'

.
.(略)
.

remote: resolve 'bootstrap-sprockets' in '/tmp/build_e08a0db1d7b9eb92bbc6b8aacfb53c4a/app/javascript/packs'
remote: Parsed request is a module
remote: using description file: /tmp/build_e08a0db1d7b9eb92bbc6b8aacfb53c4a/package.json (relative path: ./app/javascript/packs)
remote: Field 'browser' doesn't contain a valid alias configuration
remote: resolve as module
remote: looking for modules in /tmp/build_e08a0db1d7b9eb92bbc6b8aacfb53c4a/app/javascript
remote: using description file: /tmp/build_e08a0db1d7b9eb92bbc6b8aacfb53c4a/package.json (relative path: ./app/javascript)
remote: Field 'browser' doesn't contain a valid alias configuration
remote: using description file: /tmp/build_e08a0db1d7b9eb92bbc6b8aacfb53c4a/package.json (relative path: ./app/javascript/bootstrap-sprockets)

.
.(略)
.

remote: !
remote: ! Precompiling assets failed.
remote: !

該当のソースコード

Gemfile
1source 'https://rubygems.org'
2git_source(:github) { |repo| "https://github.com/#{repo}.git" }
3
4ruby '2.6.5'
5gem 'devise', '~> 4.7', '>= 4.7.1'
6gem 'paperclip', '~> 6.1'
7gem 'bootstrap-sass', '~> 3.4', '>= 3.4.1'
8gem 'jquery-rails'
9gem 'sassc-rails'
10gem 'rails', '~> 6.0.2', '>= 6.0.2.2'
11gem 'puma', '~> 4.1'
12gem 'sass-rails', '>= 6'
13gem 'webpacker', '~> 4.0'
14gem 'turbolinks', '~> 5'
15gem 'jbuilder', '~> 2.7'
16gem 'bootsnap', '>= 1.4.2', require: false
17
18group :development, :test do
19  gem 'byebug', platforms: [:mri, :mingw, :x64_mingw]
20  gem 'sqlite3', '~> 1.4'
21end
22
23group :development do
24  gem 'web-console', '>= 3.3.0'
25end
26
27group :test do
28  gem 'capybara', '>= 2.15'
29  gem 'selenium-webdriver'
30  gem 'webdrivers'
31end
32
33group :production do
34gem 'pg', '~> 1.2', '>= 1.2.3'
35end
36
37gem 'tzinfo-data', platforms: [:mingw, :mswin, :x64_mingw, :jruby]
38

webpackeryml
1# Note: You must restart bin/webpack-dev-server for changes to take effect
2
3default: &default
4  source_path: app/javascript
5  source_entry_path: packs
6  public_root_path: public
7  public_output_path: packs
8  cache_path: tmp/cache/webpacker
9  check_yarn_integrity: false
10  webpack_compile_output: true
11
12  # Additional paths webpack should lookup modules
13  # ['app/assets', 'engine/foo/app/assets']
14  resolved_paths: []
15
16  # Reload manifest.json on all requests so we reload latest compiled packs
17  cache_manifest: false
18
19  # Extract and emit a css file
20  extract_css: false
21
22  static_assets_extensions:
23    - .jpg
24    - .jpeg
25    - .png
26    - .gif
27    - .tiff
28    - .ico
29    - .svg
30    - .eot
31    - .otf
32    - .ttf
33    - .woff
34    - .woff2
35
36  extensions:
37    - .mjs
38    - .js
39    - .sass
40    - .scss
41    - .css
42    - .module.sass
43    - .module.scss
44    - .module.css
45    - .png
46    - .svg
47    - .gif
48    - .jpeg
49    - .jpg
50
51development:
52  <<: *default
53  compile: true
54
55  # Verifies that correct packages and versions are installed by inspecting package.json, yarn.lock, and node_modules
56  check_yarn_integrity: true
57
58  # Reference: https://webpack.js.org/configuration/dev-server/
59  dev_server:
60    https: false
61    host: localhost
62    port: 3035
63    public: localhost:3035
64    hmr: false
65    # Inline should be set to true if using HMR
66    inline: true
67    overlay: true
68    compress: true
69    disable_host_check: true
70    use_local_ip: false
71    quiet: false
72    pretty: false
73    headers:
74      'Access-Control-Allow-Origin': '*'
75    watch_options:
76      ignored: '**/node_modules/**'
77
78
79test:
80  <<: *default
81  compile: true
82
83  # Compile test packs to a separate directory
84  public_output_path: packs-test
85
86production:
87  <<: *default
88
89  # Production depends on precompilation of packs prior to booting for performance.
90  compile: false
91
92  # Extract and emit a css file
93  extract_css: true
94
95  # Cache manifest.json for performance
96  cache_manifest: true
97

databaseyml
1# SQLite. Versions 3.8.0 and up are supported.
2#   gem install sqlite3
3#
4#   Ensure the SQLite 3 gem is defined in your Gemfile
5#   gem 'sqlite3'
6#
7default: &default
8  adapter: sqlite3
9  pool: <%= ENV.fetch("RAILS_MAX_THREADS") { 5 } %>
10  timeout: 5000
11
12development:
13  <<: *default
14  database: db/development.sqlite3
15
16# Warning: The database defined as "test" will be erased and
17# re-generated from your development database when you run "rake".
18# Do not set this db to the same as development or production.
19test:
20  <<: *default
21  database: db/test.sqlite3
22
23production:
24  <<: *default
25  adapter: postgresql
26  encoding: unicode
27  port: 5432
28

packagejson
1{
2  "name": "winereview",
3  "private": true,
4  "dependencies": {
5    "@rails/actioncable": "^6.0.0",
6    "@rails/activestorage": "^6.0.0",
7    "@rails/ujs": "^6.0.0",
8    "@rails/webpacker": "4.2.2",
9    "bootstrap": "^4.4.1",
10    "jquery": "^3.4.1",
11    "popper.js": "^1.16.1",
12    "turbolinks": "^5.2.0"
13  },
14  "version": "0.1.0",
15  "devDependencies": {
16    "webpack-dev-server": "^3.10.3"
17  }
18  
19}
20
21

environmentjs
1const { environment } = require('@rails/webpacker')
2
3const webpack = require('webpack')
4
5
6environment.plugins.append('Provide', new webpack.ProvidePlugin({
7   $: 'jquery',
8   jQuery: 'jquery',
9   Popper: ['popper.js', 'default']
10}))
11
12module.exports = environment
13