Update mkdocstrings[python] requirement (#71)

Updates the requirements on [mkdocstrings[python]](https://github.com/mkdocstrings/mkdocstrings) to permit the latest version.
- [Release notes](https://github.com/mkdocstrings/mkdocstrings/releases)
- [Changelog](https://github.com/mkdocstrings/mkdocstrings/blob/master/CHANGELOG.md)
- [Commits](mkdocstrings/mkdocstrings@0.19.0...0.22.0)

---
updated-dependencies:
- dependency-name: mkdocstrings[python]
  dependency-type: direct:production
...

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

pyproject.toml

@@ -59,7 +59,7 @@ test = [
 ]
 doc = [
     "mkdocs-material >=9.0.0, <10.0.0",
-    "mkdocstrings[python] >=0.19.0, <0.21.0"
+    "mkdocstrings[python] >=0.19.0, <0.23.0"
 ]
 dev = [
     "pre-commit >=2.20.0, <4.0.0",