Bump pa11y-ci from 2.4.2 to 3.1.0

Bumps [pa11y-ci](https://github.com/pa11y/pa11y-ci) from 2.4.2 to 3.1.0.
- [Release notes](https://github.com/pa11y/pa11y-ci/releases)
- [Changelog](https://github.com/pa11y/pa11y-ci/blob/main/CHANGELOG.md)
- [Commits](pa11y/pa11y-ci@2.4.2...3.1.0)

---
updated-dependencies:
- dependency-name: pa11y-ci
  dependency-type: direct:development
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <[email protected]>