Bump pymongo from 3.12.1 to 4.0.1

Bumps [pymongo](https://github.com/mongodb/mongo-python-driver) from 3.12.1 to 4.0.1.
- [Release notes](https://github.com/mongodb/mongo-python-driver/releases)
- [Changelog](https://github.com/mongodb/mongo-python-driver/blob/4.0.1/doc/changelog.rst)
- [Commits](mongodb/mongo-python-driver@3.12.1...4.0.1)

---
updated-dependencies:
- dependency-name: pymongo
  dependency-type: direct:development
  update-type: version-update:semver-major
...

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

Author: dependabot[bot]

requirements_dev_optional.txt

@@ -10,7 +10,7 @@ azure-storage-blob==12.8.1 # pyup: ignore
 redis==4.0.2
 types-redis
 types-setuptools
-pymongo==3.12.1
+pymongo==4.0.1
 # optional test requirements
 tox==3.24.4
 coverage