Cross-compilation CI job

[agriyakhetarpal]

A CI job that cross-compiles wheels from the host and tests them on the target platform by exchanging wheel artifacts

• macOS arm64 to amd64 (Xcode)

• macOS amd64, arm64 to arm64, amd64 and vice versa (Zig) (doesn't currently work, related issue: Crosscompile CGO using zig 0.12 or newer ziglang/zig#20689, regression in 0.13.0?)

• macOS amd64, arm64 to Windows amd64, arm64, i686

• macOS arm64 to Linux amd64, aarch64, ppc64le, s390x (amd64 excluded because arm64 runners are faster)

• Windows amd64 to arm64, i686

• Windows amd64 to macOS amd64, arm64

• Windows amd64 to Linux amd64, aarch64 (ppc64le and s390x excluded since Docker containers needed to test)

• Linux amd64 to arm64

• Linux amd64 to macOS amd64, arm64

• Linux amd64 to Windows amd64, arm64, i686

and so on (to be decided)

[agriyakhetarpal]

linux-s390x combo does not work (have to stick with native compilation for now)

# runtime/cgo
error: unknown target CPU 'generic'
note: valid target CPU values are: arch8, z10, arch9, z196, arch10, zEC12, arch11, z13, arch12, z14, arch13, z15, arch14, z16

while ppc64le, amd64, aarch64 are working as usual.

[agriyakhetarpal]

With #163 merged, this is now easier to configure (still no MUSL support at this time, however).