Add API routes to lock and unlock issues (#34165)

This pull request adds a GitHub-compatible API endpoint to lock and
unlock an issue.

The following routes exist now:
- `PUT /api/v1/repos/{owner}/{repo}/issues/{id}/lock` to lock an issue
- `DELETE /api/v1/repos/{owner}/{repo}/issues/{id}/lock` to unlock an issue

Fixes #33677
Fixes #20012

---------

Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>

routers/api/v1/api.go

@@ -1530,6 +1530,11 @@ func Routes() *web.Router {
 								Delete(reqToken(), reqAdmin(), repo.UnpinIssue)
 							m.Patch("/{position}", reqToken(), reqAdmin(), repo.MoveIssuePin)
 						})
+						m.Group("/lock", func() {
+							m.Combo("").
+								Put(bind(api.LockIssueOption{}), repo.LockIssue).
+								Delete(repo.UnlockIssue)
+						}, reqToken(), reqAdmin())
 					})
 				}, mustEnableIssuesOrPulls)
 				m.Group("/labels", func() {