macOS platform tag changes

[nightlark]

The current HELICS 3.x installers require macos 10.14, so we should update the platform tag in compiled wheels to reflect that (instead of 10.9).

Another upcoming change will be when we start releasing universal macOS binaries, the name of the macOS binary downloaded (and the platform tag) will need updating again. The tags used by the CMake python package are macosx_10_9_universal2.macosx_10_9_x86_64.macosx_11_0_arm64.macosx_11_0_universal2, so we should consider a similar set along the lines of macosx_10_14_universal2.macosx_10_14_x86_64.macosx_11_0_arm64.macosx_11_0_universal2

[trevorhardy]

@nightlark; has this been resolved?

[nightlark]

It seems to be done.

[trevorhardy]

Closing out.