docs-builder: add pull-requests: write permission to docs-build workflow (#44946) (#45067)

(cherry picked from commit 9e9edd7)

Co-authored-by: Jan Calanog <nejcalanog@gmail.com>

Author: mergify[bot]

.github/workflows/docs-build.yml

@@ -17,4 +17,4 @@ jobs:
       deployments: write
       id-token: write
       contents: read
-      pull-requests: read
+      pull-requests: write