Bump dompurify and mermaid

Bumps [dompurify](https://github.com/cure53/DOMPurify) to 2.5.6 and updates ancestor dependency [mermaid](https://github.com/mermaid-js/mermaid). These dependencies need to be updated together.


Updates `dompurify` from 2.4.1 to 2.5.6
- [Release notes](https://github.com/cure53/DOMPurify/releases)
- [Commits](cure53/DOMPurify@2.4.1...2.5.6)

Updates `mermaid` from 9.3.0 to 11.2.1
- [Release notes](https://github.com/mermaid-js/mermaid/releases)
- [Changelog](https://github.com/mermaid-js/mermaid/blob/develop/CHANGELOG.md)
- [Commits](https://github.com/mermaid-js/mermaid/compare/[email protected])

---
updated-dependencies:
- dependency-name: dompurify
  dependency-type: indirect
- dependency-name: mermaid
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <[email protected]>