Add code owners of new MachO port

Author: gkmhub

lld/CODE_OWNERS.TXT

@@ -15,8 +15,12 @@ D: COFF, ELF backends (COFF/* ELF/*)
 
 N: Lang Hames, Nick Kledzik
 E: [email protected], [email protected]
-D: Mach-O backend
+D: Old Mach-O backend
 
 N: Sam Clegg
 E: [email protected]
 D: WebAssembly backend (wasm/*)
+
+N: Jez Ng, Greg McGary, Shoaib Meenai
+E: [email protected], [email protected], [email protected]
+D: New Mach-O backend