Add Dependabot Tapioca workflow

.github/workflows/dependabot-tapioca.yml

@@ -0,0 +1,71 @@
+name: Dependabot Tapioca
+
+on:
+  pull_request:
+    types:
+      - opened
+      - synchronize
+      - reopened
+
+permissions:
+  contents: read
+
+jobs:
+  update_tapioca:
+    if: >
+      github.actor == 'dependabot[bot]' &&
+      startsWith(github.head_ref, 'dependabot/bundler/') &&
+      github.event.pull_request.head.repo.full_name == github.repository
+    runs-on: ubuntu-latest
+    services:
+      postgres:
+        image: postgis/postgis:15-3.3
+        ports:
+          - 5432:5432
+        env:
+          POSTGRES_PASSWORD: postgres
+        options: >-
+          --health-cmd pg_isready
+          --health-interval 10s
+          --health-timeout 5s
+          --health-retries 5
+    env:
+      RAILS_ENV: test
+      DATABASE_URL: "postgis://postgres:postgres@localhost:5432/rails_test"
+    permissions:
+      contents: write
+    concurrency:
+      group: dependabot-tapioca-${{ github.event.pull_request.number }}
+      cancel-in-progress: true
+    steps:
+      - name: Checkout Dependabot branch
+        uses: actions/checkout@v6
+        with:
+          ref: ${{ github.event.pull_request.head.ref }}
+      - name: Install Ruby and gems
+        uses: ruby/setup-ruby@v1.305.0
+        with:
+          bundler-cache: true
+      - name: Create database
+        run: bin/rails db:create
+      - name: Set up database schema
+        run: bin/rails db:schema:load
+      - name: Update Tapioca RBI files
+        run: |
+          bin/tapioca gem
+          bin/tapioca dsl
+          bin/tapioca dsl --environment=test
+      - name: Commit updated RBI files
+        env:
+          PR_HEAD_REF: ${{ github.event.pull_request.head.ref }}
+        run: |
+          if git diff --quiet --exit-code -- sorbet; then
+            echo "No Tapioca changes to commit"
+            exit 0
+          fi
+
+          git config user.name "github-actions[bot]"
+          git config user.email "41898282+github-actions[bot]@users.noreply.github.com"
+          git add sorbet
+          git commit -m "Update Tapioca RBI files"
+          git push origin HEAD:$PR_HEAD_REF