Bump requests from 2.20.0 to 2.31.0 in /modules/sync

Bumps [requests](https://github.com/psf/requests) from 2.20.0 to 2.31.0.
- [Release notes](https://github.com/psf/requests/releases)
- [Changelog](https://github.com/psf/requests/blob/main/HISTORY.md)
- [Commits](https://github.com/psf/requests/compare/v2.20.0...v2.31.0)

---
updated-dependencies:
- dependency-name: requests
  dependency-type: direct:production
...

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

modules/sync/requirements.txt

@@ -6,7 +6,7 @@ pymongo==3.3.0
 PyPDF2==1.27.5
 python-frontmatter==0.3.1
 PyYAML==5.4
-requests==2.20.0
+requests==2.31.0
 six==1.10.0
 smartcrop==0.1
 toml==0.9.2