Bump pymongo from 3.3.0 to 4.6.3 in /modules/sync

Bumps [pymongo](https://github.com/mongodb/mongo-python-driver) from 3.3.0 to 4.6.3.
- [Release notes](https://github.com/mongodb/mongo-python-driver/releases)
- [Changelog](https://github.com/mongodb/mongo-python-driver/blob/master/doc/changelog.rst)
- [Commits](https://github.com/mongodb/mongo-python-driver/compare/3.3.0...4.6.3)

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

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

modules/sync/requirements.txt

@@ -2,7 +2,7 @@ cssselect==0.9.2
 lxml==4.9.1
 Markdown==2.6.6
 Pillow==10.3.0
-pymongo==3.3.0
+pymongo==4.6.3
 PyPDF2==1.27.9
 python-frontmatter==0.3.1
 PyYAML==5.4