Bump pymdown-extensions from 10.21.2 to 10.21.3 (#191)

Bumps [pymdown-extensions](https://github.com/facelessuser/pymdown-extensions) from 10.21.2 to 10.21.3.
- [Release notes](https://github.com/facelessuser/pymdown-extensions/releases)
- [Commits](facelessuser/pymdown-extensions@10.21.2...10.21.3)

---
updated-dependencies:
- dependency-name: pymdown-extensions
  dependency-version: 10.21.3
  dependency-type: direct:production
...

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Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

requirements.txt

@@ -2,4 +2,4 @@ mkdocs == 1.6.1
 mkdocs-material == 9.6.12
 mkdocs-caption == 1.3.0
 mkdocs-git-revision-date-localized-plugin == 1.4.5
-pymdown-extensions == 10.21.2
+pymdown-extensions == 10.21.3