ci: release-please integration

.github/workflows/release.yml

@@ -0,0 +1,34 @@
+name: Release
+
+on:
+  push:
+    branches:
+      - master
+
+jobs:
+  release-please:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: google-github-actions/release-please-action@v3
+        id: release
+        with:
+          release-type: ruby
+          package-name: howitzer
+          bump-minor-pre-major: true
+          bump-patch-for-minor-pre-major: true
+          version-file: "lib/howitzer/version.rb"
+          extra-files: '.deploy/Chart.yaml'
+      - uses: actions/checkout@v2
+        if: ${{ steps.release.outputs.release_created }}
+      - uses: ruby/setup-ruby@v1
+        with:
+          ruby-version: 3.0.4
+          bundler-cache: true
+        if: ${{ steps.release.outputs.release_created }}
+      - run: bundle install
+        if: ${{ steps.release.outputs.release_created }}
+      - name: Publish gem
+        run: bundle exec rake release
+        env:
+          GEM_HOST_API_KEY: "${{secrets.RUBYGEMS_AUTH_TOKEN}}"
+        if: ${{ steps.release.outputs.release_created }}