Bump the dev-dependencies group with 2 updates

Bumps the dev-dependencies group with 2 updates: [coverage](https://github.com/nedbat/coveragepy) and [ruff](https://github.com/astral-sh/ruff).


Updates `coverage` from 7.6.4 to 7.6.8
- [Release notes](https://github.com/nedbat/coveragepy/releases)
- [Changelog](https://github.com/nedbat/coveragepy/blob/master/CHANGES.rst)
- [Commits](nedbat/coveragepy@7.6.4...7.6.8)

Updates `ruff` from 0.7.1 to 0.8.1
- [Release notes](https://github.com/astral-sh/ruff/releases)
- [Changelog](https://github.com/astral-sh/ruff/blob/main/CHANGELOG.md)
- [Commits](astral-sh/ruff@0.7.1...0.8.1)

---
updated-dependencies:
- dependency-name: coverage
  dependency-type: direct:development
  update-type: version-update:semver-patch
  dependency-group: dev-dependencies
- dependency-name: ruff
  dependency-type: direct:development
  update-type: version-update:semver-minor
  dependency-group: dev-dependencies
...

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