Bump mike from 2.0.0 to 2.1.2 (#174)

Bumps [mike](https://github.com/jimporter/mike) from 2.0.0 to 2.1.2.
- [Release notes](https://github.com/jimporter/mike/releases)
- [Changelog](https://github.com/jimporter/mike/blob/master/CHANGES.md)
- [Commits](jimporter/mike@v2.0.0...v2.1.2)

---
updated-dependencies:
- dependency-name: mike
  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>

docs/requirements.txt

@@ -1,6 +1,6 @@
 jieba==0.42.1
 jinja2==3.1.4
-mike==2.0.0
+mike==2.1.2
 mkdocs-git-revision-date-localized-plugin==1.2.6
 mkdocs-markdownextradata-plugin==0.2.5
 mkdocs-material==9.5.26