Rebuild scoped Rector after a pull request is merged

Dispatches build_scoped_rector.yaml in rectorphp/rector-src, so
rectorphp/rector picks up merged changes without waiting for the next
commit to rector-src main.

Requires rectorphp/rector-src#8188, which adds the workflow_dispatch
trigger the run relies on.

Author: TomasVotruba

.github/workflows/dispatch_build_scoped_rector.yaml

@@ -0,0 +1,22 @@
+# github action that rebuilds https://github.com/rectorphp/rector
+# with the freshly merged rector-phpunit main
+name: Dispatch Build Scoped Rector
+
+on:
+    pull_request:
+        types:
+            - closed
+
+jobs:
+    dispatch_build_scoped_rector:
+        # only for merged pull requests in this repository, not forks
+        if: github.event.pull_request.merged == true && github.repository == 'rectorphp/rector-phpunit'
+
+        runs-on: ubuntu-latest
+
+        steps:
+            -
+                name: "Trigger build_scoped_rector.yaml in rectorphp/rector-src"
+                env:
+                    GH_TOKEN: ${{ secrets.ACCESS_TOKEN }}
+                run: gh workflow run build_scoped_rector.yaml --repo rectorphp/rector-src --ref main