Updating the documentation

Hi. After merging support for CrateDB, we can see a [cratedb.rst](https://github.com/testcontainers/testcontainers-python/blob/main/docs/community/cratedb.rst) in this repository, but can't find it being rendered on Read the Docs yet. Maybe an update needs to be triggered manually?

https://testcontainers-python.readthedocs.io/
