Importlib-metadata version for python 3.7

[astafan8]

what is the reason for this 'importlib-metadata<4;python_version<"3.8.0"', requirement for version 6.0.0? perhaps it could be relaxed to importlib-metadata<=4 to include 4?

[Carreau]

no, the api of version 4 is different. This was added to fix #645. Basically this mean any 3.x.y but not any 4.z.t, with the <= we would allow 4.0.0 but not 4.0.1 which is weird.

[astafan8]

thank you for the response! will be looking forward to importlib<5.0.0 support for python 3.7 :)