Perform sparse checkout

Author: mbg

.github/workflows/update-supported-enterprise-server-versions.yml

@@ -28,6 +28,7 @@ jobs:
           repository: github/enterprise-releases
           token: ${{ secrets.ENTERPRISE_RELEASE_TOKEN }}
           path: ${{ github.workspace }}/enterprise-releases/
+          sparse-checkout: releases.json
       - name: Update Supported Enterprise Server Versions
         run: |
           cd ./.github/workflows/update-supported-enterprise-server-versions/