Bump requests from 2.18.4 to 2.20.0

Bumps [requests](https://github.com/psf/requests) from 2.18.4 to 2.20.0.
- [Release notes](https://github.com/psf/requests/releases)
- [Changelog](https://github.com/psf/requests/blob/master/HISTORY.md)
- [Commits](psf/requests@v2.18.4...v2.20.0)

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

requirements.txt

@@ -20,7 +20,7 @@ pew==1.1.0
 pipenv==8.2.7
 pycodestyle==2.3.1
 pyflakes==1.5.0
-requests==2.18.4
+requests==2.20.0
 shutilwhich==1.1.0
 urllib3==1.22
 virtualenv==15.1.0