ci: set permission to add label to PR

.github/workflows/conventional-label.yaml

@@ -2,6 +2,11 @@ on:
   pull_request_target:
     types: [ opened, edited ]
 name: conventional-release-labels
+
+permissions:
+  contents: read
+  pull-requests: write
+
 jobs:
   label:
     runs-on: ubuntu-latest