Bump requests from 2.18.4 to 2.20.0

Bumps [requests](https://github.com/requests/requests) from 2.18.4 to 2.20.0.
- [Release notes](https://github.com/requests/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] <support@github.com>

Author: dependabot[bot]

requirements.txt

@@ -121,7 +121,7 @@ python-dateutil==2.7.2
 python-editor==1.0.3
 pytz==2018.4
 PyYAML==3.12
-requests==2.18.4
+requests==2.20.0
 requests-oauthlib==0.8.0
 SecretStorage==2.3.1
 six==1.11.0