Broken link in README

[ValerianRey]

The link to GeneralizedWeighting is broken: it's missing a stable/ in the URL.

[PierreQuinton]

According to gemini, this might check the links in README and CONTRIBUTING (and whatever we want):

- name: Link Checker
        uses: lycheeverse/lychee-action@v1.9.0
        with:
          # Arguments to pass to lychee
          args: --verbose --no-progress "README.md" "CONTRIBUTING.md"
          # Fail the action if broken links are found
          fail: true

I vote we add it to the test jobs.