Add release workflow to publish CRuby gem

Adds .github/workflows/release.yml triggered on v* tag pushes. Builds
the gem on CRuby 4.0, then pushes it to RubyGems via OIDC trusted
publishing (no API key secret).

Trusted publishing must be enabled for this repo on RubyGems.org
before the workflow can push gems.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: yahonda

.github/workflows/release.yml

@@ -0,0 +1,53 @@
+name: release
+
+on:
+  push:
+    tags:
+      - 'v*'
+
+jobs:
+  build-cruby:
+    name: Build gem (CRuby)
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v6
+      - name: Set up Ruby
+        uses: ruby/setup-ruby@v1
+        with:
+          ruby-version: '4.0'
+          rubygems: latest
+      - name: Build gem
+        run: gem build ruby-plsql.gemspec
+      - name: Upload gem artifact
+        uses: actions/upload-artifact@v4
+        with:
+          name: gem-cruby
+          path: "*.gem"
+
+  release:
+    name: Push gem to RubyGems
+    needs: [build-cruby]
+    runs-on: ubuntu-latest
+    environment: rubygems
+    permissions:
+      id-token: write
+      contents: read
+      actions: read
+    steps:
+      - name: Download CRuby gem
+        uses: actions/download-artifact@v4
+        with:
+          name: gem-cruby
+      - name: Set up Ruby
+        uses: ruby/setup-ruby@v1
+        with:
+          ruby-version: '4.0'
+          rubygems: latest
+      - name: Configure RubyGems credentials
+        uses: rubygems/configure-rubygems-credentials@main
+      - name: Push gem
+        run: |
+          for gem in *.gem; do
+            echo "Pushing $gem"
+            gem push "$gem"
+          done