Change Lookup field type to ecs_entity_t

src/main.zig

@@ -19,7 +19,7 @@ pub fn Context(comptime ctx: anytype) type {
 pub fn Lookup(comptime ctx: anytype, comptime T: type) type {
     _ = .{ ctx, T }; // Only necessary to create a unique type.
     return struct {
-        pub var id: c.ecs_id_t = 0;
+        pub var id: c.ecs_entity_t = 0;
     };
 }