Bump requests from 2.3.0 to 2.20.0 (#400)

* Bump requests from 2.3.0 to 2.20.0

Bumps [requests](https://github.com/requests/requests) from 2.3.0 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/v2.3.0...v2.20.0)

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

* Changelog

Co-authored-by: Stéphane Bruckert <stephane.bruckert@gmail.com>

setup.py

@@ -11,7 +11,7 @@ setup(
     author_email="paul@echonest.com",
     url='http://spotipy.readthedocs.org/',
     install_requires=[
-        'requests>=2.3.0',
+        'requests>=2.20.0',
         'six>=1.10.0',
     ],
     license='LICENSE.md',