CI: Run only Ruby 3.1 on Windows to investigate issues on it

Signed-off-by: Takuro Ashie <[email protected]>

.github/workflows/windows-test.yaml

@@ -13,22 +13,10 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        ruby-version: [3.1, '2.7', '2.6']
+        ruby-version: ['3.1']
         os:
           - windows-latest
         experimental: [false]
-        include:
-          - ruby-version: '3.0.3'
-            os: windows-latest
-            experimental: false
-            # On Ruby 3.0, we need to use fiddle 1.0.8 or later to retrieve correct
-            # error code. In addition, we have to specify the path of fiddle by RUBYLIB
-            # because RubyInstaller loads Ruby's bundled fiddle before initializing gem.
-            # See also:
-            # * https://github.com/ruby/fiddle/issues/72
-            # * https://bugs.ruby-lang.org/issues/17813
-            # * https://github.com/oneclick/rubyinstaller2/blob/8225034c22152d8195bc0aabc42a956c79d6c712/lib/ruby_installer/build/dll_directory.rb
-            ruby-lib-opt: RUBYLIB=%RUNNER_TOOL_CACHE%/Ruby/3.0.3/x64/lib/ruby/gems/3.0.0/gems/fiddle-1.1.0/lib
 
     name: Unit testing with Ruby ${{ matrix.ruby-version }} on ${{ matrix.os }}
     steps:
@@ -37,10 +25,7 @@ jobs:
         uses: ruby/setup-ruby@v1
         with:
           ruby-version: ${{ matrix.ruby-version }}
-      - name: Add Fiddle 1.1.0
-        if: ${{ matrix.ruby-version == '3.0.3' }}
-        run: gem install fiddle --version 1.1.0
       - name: Install dependencies
         run: ridk exec bundle install
       - name: Run tests
-        run: bundle exec rake test TESTOPTS=-v ${{ matrix.ruby-lib-opt }}
+        run: bundle exec rake test TESTOPTS=-v