feat: add github action to fork sync

.github/workflows/fork-sync.yml

@@ -0,0 +1,21 @@
+name: Fork Sync
+
+on:
+  schedule:
+    - cron: '0 7 * * 1,4'
+    # scheduled at 07:00 every Monday and Thursday
+
+  workflow_dispatch: # click the button on Github repo!
+
+jobs:
+  sync:
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: tgymnich/[email protected]
+        with:
+          owner: smartive
+          base: main
+          head: main
+          repo: $ionic-team/stencil
+          pr_title: Fork sync with upstream