Bump requests from 2.10.0 to 2.20.0 in /utils/Sync

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](https://github.com/requests/requests/compare/v2.10.0...v2.20.0)

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

utils/Sync/requirements.txt

@@ -6,7 +6,7 @@ pymongo==3.3.0
 PyPDF2==1.26.0
 python-frontmatter==0.3.1
 PyYAML==3.11
-requests==2.10.0
+requests==2.20.0
 six==1.10.0
 smartcrop==0.1
 toml==0.9.2