Conflict of version for urllib3 using some extensions

[idrissneumann]

Do you want to request a feature or report a bug?

Seems like a bug (non-critical)

What is the current behavior?

I've a warning in the logs of my backend container:

Trying import local.py settings...
/usr/lib/python3.7/site-packages/requests/__init__.py:91: RequestsDependencyWarning: urllib3 (1.26.2) or chardet (3.0.4) doesn't match a supported version!
  RequestsDependencyWarning)

I also have an error on the docker build:

ERROR: pip's dependency resolver does not currently take into account all the packages that are installed. This behaviour is the source of the following dependency conflicts.
requests 2.21.0 requires urllib3<1.25,>=1.21.1, but you have urllib3 1.26.2 which is incompatible.

If the current behavior is a bug, please provide the steps to reproduce.

Just pick the following Dockerfile and try to build it:

FROM dockertaiga/back

RUN pip3 install --upgrade pip && \
    pip3 install django-storages boto3 taiga-contrib-slack

What is the expected behavior?

Is it happening in taiga.io or in your own instance?

My own instance.

N.B: I've also opened an issue here because I'm not sure if it comes from the last version of taiga or the embeded version of this image.

Thanks for your help!