Build arm64-linux version for arm64

[ronaldtse]

Similar to https://github.com/metanorma/emf2svg-ruby/pull/16

[ronaldtse]

FYI @maxirmx when you have time. expressir also needs a platform gem for Windows and arm/Apple M1. Thanks!

[maxirmx]

@ronaldtse It looks like this gem is all set

[ronaldtse]

Nearly!

I see these two files doing the work:

• https://github.com/lutaml/expressir/blob/862815313231c15ffc05d98c4b49dc80f85ad464/.cross_rubies

• https://github.com/lutaml/expressir/blob/5a7d9615cf187d04549ef4bb4c6152f76b48235b/rakelib/cross-ruby.rake

  We need arm64-linux but it is not in the list yet.

[ronaldtse]

Maybe we just need to change those two files and we can add all the necessary platforms?

[maxirmx]

I see, thank you