Always run required CI check

As was realized in other projects, this conditional skipping of the step
doesn't play well with required status checks, which don't run and
therefore block the merging of PRs.

Signed-off-by: Gus Monod <gmonod1@bloomberg.net>

.github/workflows/build_wheels.yml

@@ -3,8 +3,6 @@ name: Wheels
 on:
   push:
   pull_request:
-    paths-ignore:
-      - "CONTRIBUTING.md"
   release:
     types:
       - published