Drop Python 3.7?

[jakirkham]

In Zarr PR ( zarr-developers/zarr-python#1067 ), we dropped Python 3.7. Wondering if we should do the same here. Not aware of any pain it is causing us. So we could hang onto it a bit longer if we like. Though it is worth noting that conda-forge has already dropped Python 3.7 builds.

[martindurant]

Is numpy still making wheels for 3.7?

[joshmoore]

Doesn't look like it: https://pypi.org/project/numpy/#files

[jakirkham]

Yeah they dropped Python 3.7 in NumPy 1.22.0.

That said, our usage of NumPy in Numcodecs is pretty simple (creating arrays, reshaping arrays, type conversion, etc.). So fairly old versions of NumPy work ok here.

[jakirkham]

Submitting PR ( #405 ) to drop Python 3.7

[jakirkham]

FWIW here are the PyPI stats.

Most downloads are Python 3.8 and newer. In particular Python 3.8 sees plenty of downloads generally.

Python 3.7 downloads are mostly low. Though there are a few unexplained spikes, which clamp down rather quickly.