Test with --use-system-libraries (#191)

Relates to #128

Author: stanhu

.github/workflows/test.yml

@@ -14,13 +14,19 @@ jobs:
       fail-fast: false
       matrix:
         ruby: ['3.3', '3.2', '3.1', '3.0', '2.7']
+        use_system_libraries: [false, true]
 
     steps:
       - uses: actions/checkout@v3
       - name: Set up Ruby ${{ matrix.ruby-version }}
         uses: ruby/setup-ruby@v1
         with:
           ruby-version: ${{ matrix.ruby }}
+      - name: Install libgpgme-dev
+        if: ${{ matrix.use_system_libraries }}
+        run: |
+          sudo apt install -y libgpgme-dev
+          echo "RUBY_GPGME_USE_SYSTEM_LIBRARIES=1" >> $GITHUB_ENV
       - name: Install dependencies
         run: bundle install
       - name: Run tests