Add permissions to enforce branch name workflow (#236)

Without, the commenting was broken:
https://github.com/rerun-io/rerun/actions/runs/22298987959/job/64501918434

Author: lucasmerlin

.github/workflows/enforce_branch_name.yml

@@ -4,6 +4,9 @@ on:
   pull_request_target:
     types: [opened, reopened, synchronize]
 
+permissions:
+  issues: write
+
 jobs:
   check-source-branch:
     runs-on: ubuntu-latest