Add branches-ignore (#3022)

Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>

Author: nomisRev

.github/workflows/auto-update-pr.yaml

@@ -1,6 +1,8 @@
 name: auto-update-pr
 on:
   push: {}
+  branches-ignore:
+    - main
 jobs:
   autoupdate:
     name: Auto update PR