GitLab

Deprecate install_pip function as confusing.  Move pip checks into
functions for individual platforms.

MRG: Support building arm64 and universal2 wheels on x86_64

Add `arm64` and `universal2` PLAT options.  `universal2` works by seperate Intel and ARM64 builds, and fusing the resulting wheels.

Co-authored-by: Andrew Murray <3112309+radarhere@users.noreply.github.com>

Co-authored-by: Andrew Murray <3112309+radarhere@users.noreply.github.com>

Changed functions to setup instead of wrap

Co-authored-by: Andrew Murray <3112309+radarhere@users.noreply.github.com>

This reverts commit 7a7e4632.