Update mkdocs-material to 6.1.0

[pyup-bot]

This PR updates mkdocs-material from 6.0.2 to 6.1.0.

Changelog

### 6.1.0 ``` * Fixed 1973: Added support for printing in dark mode * Fixed 1974: Added support for printing content tabs * Fixed 1995: Improved customizability of details extension mkdocs-material-6.0.2+insiders-1.6.0 (2020-10-11) * Added support for search suggestions to save keystrokes * Added support for removing 'Made with Material for MkDocs' from footer * Fixed 1915: search should go to first result by pressing Enter ```

Links

- PyPI: https://pypi.org/project/mkdocs-material - Changelog: https://pyup.io/changelogs/mkdocs-material/ - Repo: https://squidfunk.github.io/mkdocs-material/

[coveralls]

Pull Request Test Coverage Report for Build 989

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 99.133%

---

Totals
Change from base Build 981:	0.0%
Covered Lines:	1830
Relevant Lines:	1846

---

💛 - Coveralls