[Security] Bump requests from 2.19.1 to 2.20.0

Bumps [requests](https://github.com/requests/requests) from 2.19.1 to 2.20.0. **This update includes security fixes.**
- [Release notes](https://github.com/requests/requests/releases)
- [Changelog](https://github.com/requests/requests/blob/master/HISTORY.md)
- [Commits](psf/requests@v2.19.1...v2.20.0)

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

Author: dependabot-support

requirements.txt

@@ -12,7 +12,7 @@ nltk==3.2.5
 psutil==5.4.6
 pyenchant==2.0.0
 pythonwhois==2.4.3
-requests==2.19.1
+requests==2.20.0
 requests-oauthlib==1.0.0
 SQLAlchemy==1.2.10
 tweepy==3.6.0