Bump pymongo from 3.7.2 to 4.6.3

Bumps [pymongo](https://github.com/mongodb/mongo-python-driver) from 3.7.2 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](mongodb/mongo-python-driver@3.7.2...4.6.3)

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

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

setup.py

@@ -23,7 +23,7 @@
     'click==7.0',
     'Flask',
     'cerberus',
-    'pymongo==3.7.2',
+    'pymongo==4.6.3',
 ]