Bump requests from 2.18.3 to 2.20.0 (#196)

Bumps [requests](https://github.com/requests/requests) from 2.18.3 to 2.20.0.
- [Release notes](https://github.com/requests/requests/releases)
- [Changelog](https://github.com/psf/requests/blob/master/HISTORY.md)
- [Commits](https://github.com/requests/requests/compare/v2.18.3...v2.20.0)

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

requirements.txt

@@ -1,7 +1,7 @@
 pandas==0.20.3
 setuptools==40.4.3
 pytz==2017.2
-Requests==2.18.3
+Requests==2.20.0
 lxml==4.1.1
 future-fstrings
 bs4