Add pull-requests:write for test result comments

The publish-unit-test-result-action posts a comment on
the PR which requires pull-requests:write in addition to
checks:write.

Author: bschwedler

.github/workflows/ci.yml

@@ -40,6 +40,7 @@ jobs:
     permissions:
       contents: read
       checks: write
+      pull-requests: write
     runs-on: ubuntu-latest-8x
     steps:
       - name: Checkout