chore(deps): update pymdown-extensions requirement

Updates the requirements on [pymdown-extensions](https://github.com/facelessuser/pymdown-extensions) to permit the latest version.
- [Release notes](https://github.com/facelessuser/pymdown-extensions/releases)
- [Commits](facelessuser/pymdown-extensions@10.19...10.20)

---
updated-dependencies:
- dependency-name: pymdown-extensions
  dependency-version: '10.20'
  dependency-type: direct:production
...

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

Author: dependabot[bot]

requirements.txt

@@ -11,7 +11,7 @@ mkdocs-redirects ~= 1.2.2
 mkdocs-video ~= 1.5.0
 pip-audit == 2.10.0
 Pygments ~= 2.19.2
-pymdown-extensions ~= 10.19
+pymdown-extensions ~= 10.20
 PyOpenSSL ~= 25.3.0
 wheel ~= 0.45.1
 yamllint == 1.37.1