Allow depending on mruby build, support passing args to rake

[mddelk]

Changes

• update addMruby to return a build step users can use to ensure rake has already been ran
  • update example to include embedding bytecode produced by mrbc using @embedFile
  • Also supports passing in arguments to rake directly
  • NOTE: this PR targets Update mruby to v3.2.0 #4, which in turn targets Update zig to v0.11.0, add github actions CI #3