fix(CI): only run image prune after build job

Author: fubuloubu

.github/workflows/build.yaml

@@ -172,6 +172,7 @@ jobs:
             password: ${{ secrets.GITHUB_TOKEN }}
 
   prune-registry:
+    needs: build
     if: ${{ github.ref == 'refs/heads/main' }}
     runs-on: ubuntu-latest
     permissions: