[OSS-ONLY] ci: scope down permissions for manual_tags.yml (babelfish-for-postgresql#4305)

This PR updates GitHub Actions workflows to use minimal required permissions instead of the default elevated permissions.

Author: Adnan Khan

Author: AdnaneKhan

.github/workflows/manual_tags.yml

@@ -16,6 +16,9 @@ on:
       commit_hash:
         required: false
 
+permissions:
+  contents: write
+
 jobs:
   create_tag:
     runs-on: ubuntu-22.04