Bump sphinx-mdinclude from 0.5.3 to 0.6.1 (#300)

Bumps [sphinx-mdinclude](https://github.com/omnilib/sphinx-mdinclude) from 0.5.3 to 0.6.1.
- [Changelog](https://github.com/omnilib/sphinx-mdinclude/blob/main/CHANGELOG.md)
- [Commits](omnilib/sphinx-mdinclude@v0.5.3...v0.6.1)

---
updated-dependencies:
- dependency-name: sphinx-mdinclude
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>