generate x86_64 and arm64 binaries to support MacOS M1 CPU

[samuelcolvin]

Change Summary

Add arm64 binaries suitable for MacOS with an M1 CPU to PyPI.

Question 1: does this work? Can someone with an M1 mac please check.

Question 2: as per the docs it looks like x86_64 and arm64 is correct, would anyone prefer universal2 as well/instead?

Related issue number

fix #3498

[samuelcolvin]

Boundaries can be downloaded from here, click pypi_files.

[chbndrhnns]

I tried this and could run all pydantic tests fine after downloading the binaries:

git@github.com:samuelcolvin/pydantic.git
cd pydantic
python -m venv .venv
source .venv/bin/activate
pip install pydantic-1.8.2-cp39-cp39-macosx_11_0_arm64.whl
pytest tests

[samuelcolvin]

That's great, thanks.