Grant contents:write to release publish job

The repo GITHUB_TOKEN was read-only, so the create-release step 403'd.
Repo default workflow permissions are now read/write; make the publish
job's requirement explicit too.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Author: gonzalocasas

.github/workflows/release.yml

@@ -23,6 +23,8 @@ jobs:
   publish:
     needs: build
     runs-on: ubuntu-latest
+    permissions:
+      contents: write
     steps:
       - uses: compas-dev/compas-actions.publish@v3
         with: