mac rails 環境構築　エラーコードが出ていて困ってます。

https://qiita.com/nqyutq/items/5bd8ecfc3598a43a4cd1#%E3%81%AF%E3%81%98%E3%82%81%E3%81%AB
こちらのサイトを参考にmac book Airで手順を参考にさせていただいてruby on railsの環境構築をしている勉強している者です。今、３つの問題に疑問と対処方法を教えていただけると助かります。

１.以下のコードを入力して、railsをインストールしようした際に以下のエラーコードが出るんですけども、railsが最新のものであれば問題はないですか？
bundle install --path=vendor/bundle


**HEADS UP! i18n 1.1 changed fallbacks to exclude default locale.
But that may break your application.

If you are upgrading your Rails application from an older version of Rails:

Please check your Rails app for 'config.i18n.fallbacks = true'.
If you're using I18n (>= 1.1.0) and Rails (< 5.2.2), this should be
'config.i18n.fallbacks = [I18n.default_locale]'.
If not, fallbacks will be broken in your app by I18n 1.1.x.

If you are starting a NEW Rails application, you can ignore this notice.

For more info see:
https://github.com/svenfuchs/i18n/releases/tag/v1.1.0**

2.bundle exec rails new test_appを実行した結果何かのエラーと思うんですけども、これはどういう意味なんでしょうか？---

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`.
         run  bundle exec spring binstub --all
* bin/rake: Spring inserted
* bin/rails: Spring inserted
       rails  webpacker:install
Traceback (most recent call last):
	3: from bin/rails:8:in `<main>'
	2: from bin/rails:8:in `require_relative'
	1: from /Users/tanitakayuki/rails_workspace/test_app/config/boot.rb:4:in `<top (required)>'
/Users/tanitakayuki/rails_workspace/test_app/config/boot.rb:4:in `require': cannot load such file -- bootsnap/setup (LoadError)

3.rails s実行後はこのようなメッセージが出ました。これはどのようなエラーなんでしょうか？（あまりに文字数がオーバーしてしまうのですこし省略させていただきます）

Warning: the running version of Bundler (2.1.2) is older than the version that created the lockfile (2.1.4). We suggest you to upgrade to the version that created the lockfile by running `gem install bundler:2.1.4`.
=> Booting Puma
=> Rails 6.0.2.2 application starting in development 
=> Run `rails server --help` for more startup options
Exiting
Traceback (most recent call last):
〜〜〜〜〜〜〜〜〜〜〜〜〜〜〜〜〜〜〜〜〜〜〜〜〜〜〜〜〜〜〜〜〜〜〜〜〜〜〜〜〜〜
/Users/tanitakayuki/.rbenv/versions/2.7.0/lib/ruby/gems/2.7.0/gems/webpacker-4.2.2/lib/webpacker/configuration.rb:95:in `rescue in load': Webpacker configuration file not found /Users/tanitakayuki/rails_workspace/test_app/config/webpacker.yml. Please run rails webpacker:install Error: No such file or directory @ rb_sysopen - /Users/tanitakayuki/rails_workspace/test_app/config/webpacker.yml (RuntimeError)