build(deps): bump pymongo from 4.1.1 to 4.6.3 in /backend (#81)

Bumps [pymongo](https://github.com/mongodb/pymongo) from 4.1.1 to 4.6.3.
- [Commits](https://github.com/mongodb/pymongo/commits)

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

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