Bump autopep8 from 1.5.5 to 1.5.6 (#272)

Bumps [autopep8](https://github.com/hhatto/autopep8) from 1.5.5 to 1.5.6.
- [Release notes](https://github.com/hhatto/autopep8/releases)
- [Commits](hhatto/autopep8@v1.5.5...v1.5.6)

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

requirements_dev.txt

@@ -1,4 +1,4 @@
-autopep8==1.5.5
+autopep8==1.5.6
 black==20.8b1
 blacken-docs==1.10.0
 pip==21.0.1