Bump pymdown-extensions from 10.7.1 to 10.8

Bumps [pymdown-extensions](https://github.com/facelessuser/pymdown-extensions) from 10.7.1 to 10.8.
- [Release notes](https://github.com/facelessuser/pymdown-extensions/releases)
- [Commits](facelessuser/pymdown-extensions@10.7.1...10.8)

---
updated-dependencies:
- dependency-name: pymdown-extensions
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

requirements.txt

@@ -1,4 +1,4 @@
 mkdocs==1.5.3
 mkdocs-material==9.5.16
 pygments==2.17.2
-pymdown-extensions==10.7.1
+pymdown-extensions==10.8