Update HTTP status codes to modern codes (#18063)

* 2xx/3xx/4xx/5xx -> http.Status...
* http.StatusFound -> http.StatusTemporaryRedirect
* http.StatusMovedPermanently -> http.StatusPermanentRedirect

services/migrations/onedev_test.go

@@ -19,7 +19,7 @@ import (
 
 func TestOneDevDownloadRepo(t *testing.T) {
 	resp, err := http.Get("https://code.onedev.io/projects/go-gitea-test_repo")
-	if err != nil || resp.StatusCode != 200 {
+	if err != nil || resp.StatusCode != http.StatusOK {
 		t.Skipf("Can't access test repo, skipping %s", t.Name())
 	}