add write permission

Author: ealmloff

.github/workflows/preview.yml

@@ -10,6 +10,10 @@ concurrency:
   group: ${{ github.workflow }}-${{ github.event.pull_request.number || github.ref }}
   cancel-in-progress: true
 
+permissions:
+  contents: write
+  pages: write
+
 jobs:
   deploy-preview:
     if: github.event.pull_request.draft == false