fix: concurrency of automerge (#354)

prevent premature merge by enforcing ordering of actions

Author: leiicamundi

.github/workflows/automerge-global.yml

@@ -11,6 +11,16 @@ on:
                 type: string
                 default: app/renovate
 
+# Ensure only one instance of this workflow runs per PR at a time.
+# With cancel-in-progress: false, new runs wait for previous ones to complete
+# instead of cancelling them. This prevents race conditions when multiple commits
+# are pushed quickly (e.g., by Renovate rebasing), ensuring each commit's checks
+# finish before the next automerge attempt starts.
+# See example: https://github.com/camunda/camunda-deployment-references/pull/1352
+concurrency:
+    group: ${{ github.workflow }}-${{ github.ref }}
+    cancel-in-progress: false
+
 jobs:
     # do not change the name
     approve-and-auto-merge: