Bump requests from 2.2.1 to 2.20.0

Bumps [requests](https://github.com/psf/requests) from 2.2.1 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@v2.2.1...v2.20.0)

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

Author: dependabot[bot]

requirements.txt

@@ -93,7 +93,7 @@ pyxdg==0.26
 redis==2.10.5
 reportlab==3.0
 repoze.lru==0.6
-requests==2.2.1
+requests==2.20.0
 scipy==0.17.0
 sessioninstaller==0.0.0
 six==1.10.0