Remove codecov from CI
Remove `codecov` from CI.

See: https://github.com/huggingface/datasets-server/pull/2464#issuecomment-1952372916

> I personally don't really use it, and I surely didn't configure it well, because due to the monorepo structure of our repo (I think) the notifications are meaningless
Remove codecov from CI: Remove `codecov` from CI.

See: https://github.com/huggingface/datasets-server/pull/2464#issuecomment-1952372916

> I personally don't really use it, and I surely didn't configure it well, because due to the monorepo structure of our repo (I think) the notifications are meaningless