Add merge-trunk-develop-pr action

packages/github-actions/README.md

@@ -6,12 +6,14 @@ Custom GitHub actions that help to composite GitHub workflows across the repos m
 
 ## Actions list
 
+- [`automerge-released-trunk`](actions/automerge-released-trunk) - Merge `trunk` to `develop` after an extension release
 - [`branch-label`](actions/branch-label) - Set PR labels according to the branch name
 - [`coverage-report`](actions/coverage-report) - Add a clover coverage report as a PR comment
 - [`eslint-annotation`](actions/eslint-annotation) - Annotate eslint results via eslint formatter
 - [`get-plugin-releases`](actions/get-plugin-releases) - Get latest releases versions from WordPress or from a plugin.
 - [`get-release-notes`](actions/get-release-notes) - Get release notes via GitHub, infer the next version and tag
 - [`hook-documentation`](actions/hook-documentation) - Generate WordPress hook documentation
+- [`merge-trunk-develop-pr`](actions/merge-trunk-develop-pr) - Create a PR to merge `trunk` to `develop` after an extension release
 - [`phpcs-diff`](actions/phpcs-diff) - Run PHPCS to the changed lines of code, set error annotations to a pull request
 - [`prepare-extension-release`](actions/prepare-extension-release) - Create the release branch & PR with checklist
 - [`prepare-mysql`](actions/prepare-mysql) - Enable MySQL, handle authentication compatibility

packages/github-actions/actions/merge-trunk-develop-pr/README.md

@@ -0,0 +1,28 @@
+# PR to merge `trunk` to `develop`
+
+This action provides the following functionality for GitHub Actions users:
+
+- Create a PR to merge `trunk` to `develop` after a release done with the `woocommerce/grow/prepare-extension-release`
+
+## Usage
+
+See [action.yml](action.yml)
+
+#### Basic:
+
+```yaml
+name: PR to merge a released trunk
+
+on:
+  pull_request:
+    types:
+      - closed
+    branches:
+      - trunk
+
+jobs:
+  automerge_trunk:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: woocommerce/grow/merge-trunk-develop-pr@actions-v1
+```

packages/github-actions/actions/merge-trunk-develop-pr/action.yml

@@ -0,0 +1,19 @@
+name: Merge `trunk` to `develop` PR
+description: Create a PR to merge `trunk` to `develop` after a release
+
+runs:
+  using: composite
+  steps:
+    - name: "Make the PR"
+      if: ${{ github.event.pull_request.merged == true && startsWith(github.head_ref, 'release/') && github.event.pull_request.user.login == 'github-actions[bot]' }}
+      uses: actions/github-script@v6
+      with:
+        script: |
+          const title = '${{github.event.pull_request.title}} - Merge `trunk` to `develop`';
+          const opts = await github.rest.pulls.create( {
+            ...context.repo,
+            base: 'develop',
+            head: 'trunk',
+            title,
+            body: '${{ github.event.pull_request.html_url }}',
+          } );