Backport #29554 by @lng2020
As title.
The former code directly used `ctx.Repo.GitRepo`, causing 500.
22b4f0c09f/routers/api/v1/repo/release.go (L241)
Co-authored-by: Nanguan Lin <nanguanlin6@gmail.com>
(cherry picked from commit b84303ef6e73e2436f0c4c3985020be6bbbb5d1e)