Update pymongo library #494
Description
The Pymongo library is 2 major versions behind. It's pinned in the opaque-keys repo but doesn't seem to be used in there at all. It's also not pinned in edx-platform and probably should be until we're ready to do this upgrade. It's also being pulled in from:
- event-tracking
- mongoengine
- openedx-mongodbproxy # This one in particular is probably not needed anymore as a lot of its features are now part of the core mongo client? But we'll need to verify that