ci: scope down permissions for label_pr_on_title.yml

Author: AdnaneKhan

.github/workflows/label_pr_on_title.yml

@@ -6,6 +6,9 @@ on:
     types:
       - completed
 
+permissions:
+  pull-requests: write
+
 jobs:
   get_pr_details:
     # Guardrails to only ever run if PR recording workflow was indeed