Bump pymongo from 4.8.0 to 4.15.1

Bumps [pymongo](https://github.com/mongodb/mongo-python-driver) from 4.8.0 to 4.15.1.
- [Release notes](https://github.com/mongodb/mongo-python-driver/releases)
- [Changelog](https://github.com/mongodb/mongo-python-driver/blob/master/doc/changelog.rst)
- [Commits](mongodb/mongo-python-driver@4.8.0...4.15.1)

---
updated-dependencies:
- dependency-name: pymongo
  dependency-version: 4.15.1
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

Author: dependabot[bot]

requirements.txt

@@ -10,7 +10,7 @@ itsdangerous==2.2.0
 markdown==3.5
 requests==2.32.3
 Flask-Session2==1.3.1
-pymongo==4.8.0
+pymongo==4.15.1
 Flask-mde==1.2.1
 Flask-login==0.6.3
 arrow==1.3.0