Update mkdocstrings-python requirement from >=0.8,<1.6 to >=0.8,<1.7

Updates the requirements on [mkdocstrings-python](https://github.com/mkdocstrings/python) to permit the latest version.
- [Release notes](https://github.com/mkdocstrings/python/releases)
- [Changelog](https://github.com/mkdocstrings/python/blob/main/CHANGELOG.md)
- [Commits](mkdocstrings/python@0.8.0...1.6.0)

---
updated-dependencies:
- dependency-name: mkdocstrings-python
  dependency-type: direct:development
...

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

pyproject.toml

@@ -31,7 +31,7 @@ pylint-pytest = "^1.1.2"
 mkdocs = "^1.4.2"
 mkdocs-material = "^9.0.2"
 mkdocstrings = ">=0.20,<0.23"
-mkdocstrings-python = ">=0.8,<1.6"
+mkdocstrings-python = ">=0.8,<1.7"
 
 [tool.poetry.dependencies]
 python = "^3.8"