Bump requests from 2.10.0 to 2.20.0

Bumps [requests](https://github.com/requests/requests) from 2.10.0 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@v2.10.0...v2.20.0)

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

dev-requirements.txt

@@ -9,6 +9,6 @@ pbr==1.10.0
 python-dateutil==2.5.3
 python-termstyle==0.1.10
 rednose==1.1.1
-requests==2.10.0
+requests==2.20.0
 requests-mock==1.1.0
 six==1.10.0

requirements.txt

@@ -1,5 +1,5 @@
 cachetools==3.0.0
-requests==2.10.0
+requests==2.20.0
 six==1.10.0
 python-dateutil==2.5.3
 Cython==0.29.14