Bump autoflake from 1.5.3 to 1.6.0

Bumps [autoflake](https://github.com/PyCQA/autoflake) from 1.5.3 to 1.6.0.
- [Release notes](https://github.com/PyCQA/autoflake/releases)
- [Commits](PyCQA/autoflake@v1.5.3...v1.6.0)

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

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

requirements-dev.txt

@@ -6,7 +6,7 @@ flake8==4.0.1
 pydocstyle==6.1.1
 docformatter==1.5.0
 coverage==6.4.4
-autoflake==1.5.3
+autoflake==1.6.0
 tox==3.26.0
 pur==7.0.0
 wheel==0.37.1