Bump the dev-dependencies group in /backend with 4 updates

Bumps the dev-dependencies group in /backend with 4 updates: [coverage](https://github.com/nedbat/coveragepy), [mypy](https://github.com/python/mypy), [ruff](https://github.com/astral-sh/ruff) and [types-tabulate](https://github.com/python/typeshed).


Updates `coverage` from 7.6.8 to 7.6.10
- [Release notes](https://github.com/nedbat/coveragepy/releases)
- [Changelog](https://github.com/nedbat/coveragepy/blob/master/CHANGES.rst)
- [Commits](nedbat/coveragepy@7.6.8...7.6.10)

Updates `mypy` from 1.13.0 to 1.14.1
- [Changelog](https://github.com/python/mypy/blob/master/CHANGELOG.md)
- [Commits](python/mypy@v1.13.0...v1.14.1)

Updates `ruff` from 0.8.1 to 0.8.4
- [Release notes](https://github.com/astral-sh/ruff/releases)
- [Changelog](https://github.com/astral-sh/ruff/blob/main/CHANGELOG.md)
- [Commits](astral-sh/ruff@0.8.1...0.8.4)

Updates `types-tabulate` from 0.9.0.20240106 to 0.9.0.20241207
- [Commits](https://github.com/python/typeshed/commits)

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

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