Unable to disable request timeout

[153957]

Previously it was possible to disable the timeout for the HTTP client by setting request_timeout to None, but after: #257 it 'has' to be an int of float.
So the timeout can no longer be easily disabled (can of course be set super high, but that means having to set it to something instead of clearly nothing/unlimited).

Please allow None as a value for the request_timeout.

[aMahanna]

Hey @153957, #265 should fix the mypy issue you are seeing

[153957]

Thank you!