build(deps): bump tzinfo from 1.2.9 to 1.2.10 in /docs

Bumps [tzinfo](https://github.com/tzinfo/tzinfo) from 1.2.9 to 1.2.10.
- [Release notes](https://github.com/tzinfo/tzinfo/releases)
- [Changelog](https://github.com/tzinfo/tzinfo/blob/master/CHANGES.md)
- [Commits](https://github.com/tzinfo/tzinfo/compare/v1.2.9...v1.2.10

)

---
updated-dependencies:
- dependency-name: tzinfo
  dependency-type: indirect
...

Signed-off-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Signed-off-by: Fabio Utzig <utzig@apache.org>