Update dependency mkdocs-material to v9.5.21

[renovate[bot]]

This PR contains the following updates:

Package	Change	Age	Adoption	Passing	Confidence
mkdocs-material (changelog)	==9.5.20 -> ==9.5.21

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Release Notes

squidfunk/mkdocs-material (mkdocs-material)

### [`v9.5.21`](https://togithub.com/squidfunk/mkdocs-material/releases/tag/9.5.21): mkdocs-material-9.5.21 [Compare Source](https://togithub.com/squidfunk/mkdocs-material/compare/9.5.20...9.5.21) - Fixed [#​7133](https://togithub.com/squidfunk/mkdocs-material/issues/7133): Ensure latest version of Mermaid.js is used - Fixed [#​7125](https://togithub.com/squidfunk/mkdocs-material/issues/7125): Added warning for dotfiles in info plugin Thanks to [@​kamilkrzyskow](https://togithub.com/kamilkrzyskow) for their contributions

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