api: support listing repository tags (#6656)

Co-authored-by: zhouzhibo <zhouzhibo>
Co-authored-by: Joe Chen <jc@unknwon.io>

internal/route/api/v1/api.go

@@ -280,6 +280,7 @@ func RegisterRoutes(m *macaron.Macaron) {
 					m.Get("/:sha", repo.GetRepoGitTree)
 				})
 				m.Get("/forks", repo.ListForks)
+				m.Get("/tags", repo.ListTags)
 				m.Group("/branches", func() {
 					m.Get("", repo.ListBranches)
 					m.Get("/*", repo.GetBranch)