Assert MongoDB supported versions

Context

Currently the MongoDB Connector tries to support versions from 3.2 till 4.0

The integrations tests are incomplete thus making it hard to show those versions as supported.

Proposed solution

Implement integration tests for all(or almost) know operations documented by mongo:
https://docs.mongodb.com/v3.6/reference/operator/update/#fields
https://docs.mongodb.com/v3.6/reference/operator/update/#array
https://docs.mongodb.com/v3.6/reference/operator/update/#modifiers
https://docs.mongodb.com/v3.6/reference/operator/update/#bitwise