Bump flake8 from 3.9.1 to 3.9.2 (#28)

Bumps [flake8](https://gitlab.com/pycqa/flake8) from 3.9.1 to 3.9.2.
- [Release notes](https://gitlab.com/pycqa/flake8/tags)
- [Commits](https://gitlab.com/pycqa/flake8/compare/3.9.1...3.9.2)

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

setup.py

@@ -43,7 +43,7 @@ setup(
         'dev': [
             'nose==1.3.7',
             'coveralls==3.1.0',
-            'flake8==3.9.1'
+            'flake8==3.9.2'
         ]
     },
     zip_safe=False