Bump pymongo from 3.9.0 to 3.11.4 (#742)

Bumps [pymongo](https://github.com/mongodb/mongo-python-driver) from 3.9.0 to 3.11.4.
- [Release notes](https://github.com/mongodb/mongo-python-driver/releases)
- [Changelog](https://github.com/mongodb/mongo-python-driver/blob/3.11.4/doc/changelog.rst)
- [Commits](mongodb/mongo-python-driver@3.9.0...3.11.4)

Signed-off-by: dependabot[bot] <[email protected]>

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

requirements_dev_optional.txt

@@ -8,7 +8,7 @@ ipytree==0.1.3
 # version to get compatibility with azure storage emulator on appveyor (FIXME)
 azure-storage-blob==2.0.1 # pyup: ignore
 redis==3.3.8
-pymongo==3.9.0
+pymongo==3.11.4
 # optional test requirements
 tox==3.14.0
 coverage