Async DNS requests for mruby as a binding for https://c-ares.org/

[Asmod4n]

No description provided.

[dearblue]

@Asmod4n,
Since there is no branch specification in the mruby-c-ares.gem file, the mruby build system tries to reference the master branch.
However, the mruby-c-ares repository does not have a master branch, so an error occurs.

I recommend adding branch: main to your mruby-c-ares.gem file, or adding a master branch to your mruby-c-ares repository.