Support for Python 3.7

[giswqs]

I am trying to integrate eerepr into geemap. Just noticed that eerepr requires Python >=3.8. Any reason why Python 3.7 is not supported? Since Colab still uses Python 3.7, although I can use pip install eerepr --ignore-requires-python to install it, it is not ideal as a dependency for other packages.

[aazuspan]

Hi @giswqs, I was hoping to avoid supporting 3.7 since the Numpy support schedule recommended dropping it a year ago, but since Colab is still stuck on it and this is the second request (see #13), I'll break down and add support with the next release. I'll keep you posted.