Bump requests from 2.12.1 to 2.20.0

Bumps [requests](https://github.com/requests/requests) from 2.12.1 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@v2.12.1...v2.20.0)

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

requirements.txt

@@ -21,7 +21,7 @@ mysqlclient==1.3.14
 pycparser==2.19
 pygeoip==0.3.2
 pyOpenSSL==18.0.0
-requests==2.12.1
+requests==2.20.0
 six==1.12.0
 SQLAlchemy==1.2.16
 urllib3==1.24.1