Update workflow file to have write access to push tags (babelfish-for-postgresql#716)

Author: shardgupta

.github/workflows/manual_tags.yml

@@ -22,6 +22,8 @@ permissions:
 jobs:
   create_tag:
     runs-on: ubuntu-latest
+    permissions:
+      contents: write
 
     steps:
       - uses: actions/checkout@v2