cb7ba8969d
Backport #24470 Fixes #24145 --- To solve the bug, I added a "computed" `TargetBehind` field to the `Release` model, which indicates the target branch of a release. This is particularly useful if the target branch was deleted in the meantime (or is empty). I also did a micro-optimization in `calReleaseNumCommitsBehind`. Instead of checking that a branch exists and then call `GetBranchCommit`, I immediately call `GetBranchCommit` and handle the `git.ErrNotExist` error. This optimization is covered by the added unit test. _contributed in the context of @forgejo_