Add ability to rewrite GitHub URLs to issues/PRs from other organizations to avoid backlinks

[mschoettle]

We have lots of dependency updates merge requests that were created by Renovate and include the changelog. Some of those include references to GitHub issues or pull requests on the repository of the dependency. By default, GitHub creates a backlink from the linked item to the linking item.

Dependabot and Renovate Bot change those URLs to redirect.github.com instead of github.com to avoid spamming other repos with backlinks.

It would be great to have the ability to have this, maybe as an option?

[spruce]

Sounds good. I just don't have the time to add it currently. I would be willing to accept a PR for this feature.