Fix division by zero error in ecosystem check (#11469)
e.g.
https://github.com/astral-sh/ruff/actions/runs/9144809516/job/25143076896?pr=11468
<img width="1388" alt="Screenshot 2024-05-19 at 12 02 15 AM"
src="https://github.com/astral-sh/ruff/assets/2586601/0df7cbcd-712c-4ea9-96f5-73f871570525">
