Yanked release and version comparison links slightly wrong

[marcaddeo]

When you yank a release the next release is still using it in it's comparison link.. This is probably not ideal.

For example:

## [5.10.1] - 2020-01-02

## 5.10.0 - 2020-01-02 [YANKED]

## [5.9.5] - 2019-12-22

[5.10.1]: https://github.com/my/repo/compare/5.10.0...5.10.1

I think ideally this would go back to the previous release that is not yanked.

## [5.10.1] - 2020-01-02

## 5.10.0 - 2020-01-02 [YANKED]

## [5.9.5] - 2019-12-22

[5.10.1]: https://github.com/my/repo/compare/5.9.5...5.10.1

[marcaddeo]

Looked into this a tad more. Making this behave better would likely best be implemented in Release::yank() so that when you yank a release, it fixes the associated links as well.