ci: Package action automatically on release branch (#15)

.github/workflows/package-action.yaml

@@ -0,0 +1,35 @@
+name: "Package Action"
+
+on:
+  push:
+    branches:
+      - "main"
+
+env:
+  source: "main"
+  release: "release"
+
+jobs:
+  package-changes:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+        with:
+          ref: "${{ env.release }}"
+          fetch-depth: 0
+          ssh-key: "${{ secrets.COMMIT_KEY }}"
+      - uses: pr-mpt/actions-merge-branch@v2
+        with:
+          from: "origin/${{ env.source }}"
+          commit: false
+      - name: Install Javascript dependencies with npm
+        run: npm install
+      - name: Package action for distribution
+        run: npm run package
+      - name: Push packaged action to branch
+        uses: EndBug/add-and-commit@v7
+        with:
+          add: "['.', 'dist --force']"
+          branch: "${{ env.release }}"
+          default_author: github_actions
+          message: "build: Package action as `dist` with latest changes"