feat(ci): Add sync workflow (#288)

.github/workflows/sync.yml

@@ -0,0 +1,37 @@
+name: Sync PR to other branches
+on:
+  pull_request:
+    types:
+      - closed
+    branches:
+      - main
+
+jobs:
+  sync:
+    if: github.event.pull_request.merged == true
+    runs-on: ubuntu-latest
+    steps:
+      - name: Setup Git
+        run: |
+          mkdir -p ${{ runner.temp }}
+          echo "${{ secrets.SSH_SIGNING_KEY }}" > ${{ runner.temp }}/signing_key
+          chmod 0700 ${{ runner.temp }}/signing_key
+          git config --global --add safe.directory "$GITHUB_WORKSPACE"
+          git config user.name "Raboneko"
+          git config user.email "[email protected]"
+          git config gpg.format "ssh"
+          git config user.signingkey "${{ runner.temp }}/signing_key"
+      - name: Checkout
+        uses: actions/checkout@v3
+        with:
+          fetch-depth: 0
+          ssh-key: ${{ secrets.SSH_AUTHENTICATION_KEY }}
+      - name: Download patches
+        run: |
+          curl https://github.com/terrapkg/packages/pull/${{ github.event.pull_request.number }}.patch > pr.patch
+      - name: Apply patches
+        run: |
+          git checkout f38
+          git am --keep-cr --signoff < pr.patch
+      - name: Push
+        run: git push origin -u --all