[CI] Explicitly bundle gemfied stdlib gems

Author: amatsuda

Diff for: .github/workflows/ruby.yml

@@ -60,6 +60,7 @@ jobs:
             rails-version: '7.2'
 
     env:
+      RUBY_VERSION: ${{ matrix.ruby-version }}
       RAILS_VERSION: ${{ matrix.rails-version }}
     steps:
     - uses: actions/checkout@v4

Diff for: Gemfile

@@ -10,3 +10,10 @@ if ENV['RAILS_VERSION']
 else
   gem 'rails'
 end
+
+if ENV['RUBY_VERSION'] >= '3.3'
+  gem 'mutex_m'
+  gem 'base64'
+  gem 'bigdecimal'
+  gem 'drb'
+end