remove root xmake.lua (#1839)

* fix code owners

* rm code owners

* remove root xmake.lua

* add code owners

xmake.lua

@@ -1,7 +0,0 @@
-
--- set xmake minimal version
-set_xmakever("2.3.8")
-
--- set repository description
-set_description("The official package repository of xmake")
-