Bump pydocstyle from 5.1.1 to 6.0.0 (#154)

Bumps [pydocstyle](https://github.com/PyCQA/pydocstyle) from 5.1.1 to 6.0.0.
- [Release notes](https://github.com/PyCQA/pydocstyle/releases)
- [Changelog](https://github.com/PyCQA/pydocstyle/blob/master/docs/release_notes.rst)
- [Commits](PyCQA/pydocstyle@5.1.1...6.0.0)

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

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

requirements_lint.txt

@@ -1,4 +1,4 @@
 black==20.8b1
 flake8==3.9.0
-pydocstyle==5.1.1
+pydocstyle==6.0.0
 pylint==2.7.2