Compatibility python3.6

[VincentDB]

Hello, i'm actually using this project in a python3.6 environment and it's working well. Well done. But in the setup.py, it's specified python_requires='>=3.7' so i can't build a package in my virtualenv.

[jchanvfx]

Hey @VincentDB ,

Thanks for checking out the framework I've just updated the setup.py in the master branch 😃

Cheers,
Johnny