fix(workflow): gh-pages requests necessary permissions (#286)

Will be mirrored by datahub-project#10953

.github/workflows/documentation.yml

@@ -27,6 +27,8 @@ concurrency:
 jobs:
   gh-pages:
     runs-on: ubuntu-latest
+    permissions:
+      contents: write
     steps:
       # We explicitly don't use acryldata/sane-checkout-action because docusaurus runs
       # git commands to determine the last change date for each file.