fix: automate commit-to-publish workflow

Use googleapis/release-please-action and rubygems/release-gem actions
to automate releasing and publishing new gem versions to rubygems.

Author: jcouball

.github/workflows/release.yml

@@ -0,0 +1,51 @@
+---
+name: Release Gem
+description: |
+  This workflow creates a new release on GitHub and publishes the gem to
+  RubyGems.org.
+
+  The workflow uses the `googleapis/release-please-action` to handle the
+  release creation process and the `rubygems/release-gem` action to publish
+  the gem.
+
+on:
+  push:
+    branches: ["main"]
+
+  workflow_dispatch:
+
+jobs:
+  release:
+    runs-on: ubuntu-latest
+
+    environment:
+      name: RubyGems
+      url: https://rubygems.org/gems/ruby_git
+
+    permissions:
+      contents: write
+      pull-requests: write
+      id-token: write
+
+    steps:
+      - name: Checkout project
+        uses: actions/checkout@v4
+
+      - name: Create release
+        uses: googleapis/release-please-action@v4
+        id: release
+        with:
+          token: ${{ secrets.AUTO_RELEASE_TOKEN }}
+          config-file: release-please-config.json
+          manifest-file: .release-please-manifest.json
+
+      - name: Setup ruby
+        uses: ruby/setup-ruby@v1
+        if: ${{ steps.release.outputs.release_created }}
+        with:
+          bundler-cache: true
+          ruby-version: ruby
+
+      - name: Push to RubyGems.org
+        uses: rubygems/release-gem@v1
+        if: ${{ steps.release.outputs.release_created }}

.release-please-manifest.json

@@ -0,0 +1,3 @@
+{
+  ".": "0.3.1"
+}

Rakefile

@@ -17,6 +17,13 @@ Bundler::Audit::Task.new
 require 'bundler'
 require 'bundler/gem_tasks'
 
+# Make it so that calling `rake release` just calls `rake release:rubygems_push` to
+# avoid creating and pushing a new tag.
+
+Rake::Task['release'].clear
+desc 'Customized release task to avoid creating a new tag'
+task release: 'release:rubygem_push'
+
 # RSpec
 
 require 'rspec/core/rake_task'

release-please-config.json

@@ -0,0 +1,22 @@
+{
+  "bootstrap-sha": "b03a7aebb563e4a25eca7f664dd39c7a0595eb61",
+  "packages": {
+    ".": {
+      "release-type": "ruby",
+      "package-name": "ruby_git",
+      "changelog-path": "CHANGELOG.md",
+      "version-file": "lib/ruby_git/version.rb",
+      "bump-minor-pre-major": true,
+      "bump-patch-for-minor-pre-major": true,
+      "draft": false,
+      "prerelease": false,
+      "include-component-in-tag": false
+    }
+  },
+  "plugins": [
+    {
+      "type": "sentence-case"
+    }
+  ],
+  "$schema": "https://raw.githubusercontent.com/googleapis/release-please/main/schemas/config.json"
+}