Please upgrade to support pytest >= 5.4.1

[michaelwiles]

Please upgrade to support pytest ^5.4.1

Get this error on poetry:

Because pytest-docker-py (1.1.3) depends on pytest (4.0.0)
and no versions of pytest-docker-py match >1.1.3,<2.0.0, pytest-docker-py (>=1.1.3,<2.0.0) requires pytest (4.0.0).
So, because app depends on both pytest-docker-py (^1.1.3) and pytest (^5.4.1), version solving failed.