ci: Revert Bundler 4.0.6 pin and use rubygems: latest

.github/workflows/rubocop.yml

@@ -10,21 +10,14 @@ jobs:
   build:
 
     runs-on: ubuntu-latest
-    env:
-      BUNDLER_VERSION: 4.0.6
 
     steps:
     - uses: actions/checkout@v6
     - name: Set up Ruby 4.0
       uses: ruby/setup-ruby@v1
       with:
         ruby-version: "4.0"
-    - name: Pin Bundler to 4.0.6 (workaround for ruby/rubygems#9536)
-      run: |
-        gem install bundler -v 4.0.6
-        ruby --version
-        gem --version
-        bundle --version
+        rubygems: latest
     - name: Build and run RuboCop
       run: |
         BUNDLE_ONLY=rubocop bundle install --jobs 4 --retry 3

.github/workflows/test.yml

@@ -50,6 +50,7 @@ jobs:
       uses: ruby/setup-ruby@v1
       with:
         ruby-version: ${{ matrix.ruby }}
+        rubygems: latest
     - name: Create symbolic link for libaio library compatibility
       run: |
         sudo ln -s /usr/lib/x86_64-linux-gnu/libaio.so.1t64 /usr/lib/x86_64-linux-gnu/libaio.so.1

.github/workflows/test_11g.yml

@@ -56,6 +56,7 @@ jobs:
       uses: ruby/setup-ruby@v1
       with:
         ruby-version: ${{ matrix.ruby }}
+        rubygems: latest
     - name: Create symbolic link for libaio library compatibility
       run: |
         sudo ln -s /usr/lib/x86_64-linux-gnu/libaio.so.1t64 /usr/lib/x86_64-linux-gnu/libaio.so.1

.github/workflows/test_11g_ojdbc11.yml

@@ -52,6 +52,7 @@ jobs:
       uses: ruby/setup-ruby@v1
       with:
         ruby-version: ${{ matrix.ruby }}
+        rubygems: latest
     - name: Create symbolic link for libaio library compatibility
       run: |
         sudo ln -s /usr/lib/x86_64-linux-gnu/libaio.so.1t64 /usr/lib/x86_64-linux-gnu/libaio.so.1