Use "ok" for successful changelog updates

This is more accurate because the "no changelog" label also makes this succeed without actually updating the changelog.

.github/workflows/report.yml

@@ -127,7 +127,7 @@ jobs:
  - name: Provide success badge
  id: changelog
  run: |
- echo "badge=https://img.shields.io/badge/CHANGELOG-updated-brightgreen.svg?style=flat" >> "$GITHUB_OUTPUT"
+ echo "badge=https://img.shields.io/badge/CHANGELOG-ok-brightgreen.svg?style=flat" >> "$GITHUB_OUTPUT"
 
  - name: Provide failure badge
  id: changelog-failure