patterns/upk-ue3: Add magic pragma (#436)

Author: Vemmi

patterns/upk-ue3.hexpat

@@ -1,5 +1,6 @@
 #pragma description Unreal Engine 3 UPK
 #pragma endian little
+#pragma magic [ c1 83 2a 9e ] @ 0x00
 
 import std.io;