Version 0.15.6

What's Changed

This release introduces a bug fix:

1. Allow issue-validator to accept valid issue references from external repositories. Previously, it was intended for the validator to not accept any references outside the current repository as I don't find an use-case for it. However #126 presented a use-case for it. Thanks for the heads-up @Th3S4mur41!

Full Changelog: v0.15.5...v0.15.6