wait for status checks to finish before attempting to merge

allow manual triggering

Author: ralfhandl

.github/workflows/sync-dev-to-vX.Y-dev.yaml

@@ -8,6 +8,7 @@ name: sync-dev-to-vX.Y-dev
 
 # run this on push to dev
 on:
+  workflow_dispatch: {} # for testing only
   push:
     branches:
       - dev
@@ -46,6 +47,8 @@ jobs:
               --label "Housekeeping" \
               --title "$BASE: update from $HEAD" \
               --body "Merge \`$HEAD\` into \`$BASE\`.")
+            
+            gh pr checks $PR --fail-fast --watch
             gh pr merge $PR --merge --admin
           done
         env: