Add myself to MAINTAINERS (go-gitea#20786)

PEN² · lunny · Sysoev, Vladimir · commit 6cbf0c21d436 · 2022-08-28T20:23:05.000+03:00
Co-authored-by: Lunny Xiao &lt;xiaolunwen@gmail.com&gt;
diff --git a/MAINTAINERS b/MAINTAINERS
@@ -47,3 +47,4 @@ Leon Hofmeister <dev.lh@web.de> (@delvh)
 Gusted <williamzijl7@hotmail.com) (@Gusted)
 silentcode <silentcode@senga.org> (@silentcodeg)
 Wim <wim@42.be> (@42wim)
+xinyu <xinyu@nerv.org.cn> (@penlinux)
