Bump mkdocstrings-python from 0.7.1 to 0.8.3 in /docs/user (#253)

Bumps [mkdocstrings-python](https://github.com/mkdocstrings/python) from 0.7.1 to 0.8.3.
- [Release notes](https://github.com/mkdocstrings/python/releases)
- [Changelog](https://github.com/mkdocstrings/python/blob/master/CHANGELOG.md)
- [Commits](mkdocstrings/python@0.7.1...0.8.3)

---
updated-dependencies:
- dependency-name: mkdocstrings-python
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

docs/user/requirements.txt

@@ -1,7 +1,7 @@
 mkdocs==1.4.0
 mkdocs-material==8.5.6
 mkdocstrings[python]==0.20.0
-mkdocstrings-python==0.7.1
+mkdocstrings-python==0.8.3
 markdown-include==0.8.0
 mkdocs-gen-files==0.4.0
 mkdocs-exclude==1.0.2