Add ability to specify another repository

[3ach]

This pull request allows a repository input which will cause the release to be created in another repository. We would like to use this to trigger matched releases across different tools using GitHub Actions.

[calavera]

It'd be great to get this merged, it's a super useful feature specially when you want to keep code private but releases public.

[chrisreddington]

If i'm reading this correctly, is this a duplicate of #96? Looks like that PR has been merged