Only run pr_labeler on devel or stable-* branches (#2552) (#2602)

(cherry picked from commit a2067ce)

Co-authored-by: Lyle McKarns <[email protected]>

Author: patchback[bot]

.github/workflows/labeler.yml

@@ -4,6 +4,9 @@
 
 "on":
   pull_request_target:
+    branches:
+      - devel
+      - "stable-*"
   issues:
     types:
       - opened