⬆️ Bump pip from 21.0 to 21.0.1

Bumps [pip](https://github.com/pypa/pip) from 21.0 to 21.0.1.
- [Release notes](https://github.com/pypa/pip/releases)
- [Changelog](https://github.com/pypa/pip/blob/master/NEWS.rst)
- [Commits](pypa/pip@21.0...21.0.1)

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

Author: dependabot[bot]

requirements_dev.txt

@@ -1,7 +1,7 @@
 autopep8==1.5.4
 black==20.8b1
 blacken-docs==1.9.2
-pip==21.0
+pip==21.0.1
 pre-commit==2.10.0
 twine==3.3.0
 wheel==0.36.2