Merge pull request #438 from holly-cummins/fix-syncbot-fork-permissions

Fix syncbot permissions for fork PRs by using `pull_request_target`

Author: holly-cummins

.github/workflows/syncbot.yml

@@ -1,7 +1,7 @@
 name: Branch sync
 
 on:
-  pull_request:
+  pull_request_target:
     branches:
       - main
       - ootb