fix: support www.github.com` for migrations

(cherry picked from commit 284ffe4)

Author: viceice

services/migrations/github.go

@@ -45,6 +45,11 @@ func (f *GithubDownloaderV3Factory) New(ctx context.Context, opts base.MigrateOp
 		return nil, err
 	}
 
+	// some users are using the github redirect url for migration
+	if u.Host == "www.github.com" {
+		u.Host = "github.com"
+	}
+
 	baseURL := u.Scheme + "://" + u.Host
 	fields := strings.Split(u.Path, "/")
 	oldOwner := fields[1]