Bump requests from 1.2.0 to 2.20.0 in /coinbase_oauth2

Bumps [requests](https://github.com/requests/requests) from 1.2.0 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@v1.2.0...v2.20.0)

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

Author: dependabot[bot]

coinbase_oauth2/requirements.txt

@@ -4,5 +4,5 @@ Pygments==1.6
 Werkzeug==0.8.3
 httplib2==0.8
 oauth2client==1.1
-requests==1.2.0
+requests==2.20.0
 wsgiref==0.1.2