build(deps-dev): bump pygments from 2.19.2 to 2.21.0

Bumps [pygments](https://github.com/pygments/pygments) from 2.19.2 to 2.21.0.
- [Release notes](https://github.com/pygments/pygments/releases)
- [Changelog](https://github.com/pygments/pygments/blob/master/CHANGES)
- [Commits](pygments/pygments@2.19.2...2.21.0)

---
updated-dependencies:
- dependency-name: pygments
  dependency-version: 2.21.0
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

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

Author: dependabot[bot]

pyproject.toml

@@ -35,7 +35,7 @@ docs = [
     "markdown-include",
     "pymdown-extensions",
     "Markdown",
-    "pygments<2.20",
+    "pygments<2.22",
 ]
 
 [build-system]