Add permissions block to Workflows

.github/workflows/update-changelog.yaml

@@ -8,6 +8,12 @@ jobs:
   update:
     runs-on: ubuntu-latest
 
+    permissions:
+      # Give the default GITHUB_TOKEN write permission to commit and push the
+      # updaetd CHANGELOG back to the repository.
+      # https://github.blog/changelog/2023-02-02-github-actions-updating-the-default-github_token-permissions-to-read-only/
+      contents: write
+
     steps:
       - name: Checkout code
         uses: actions/checkout@v3