“_used_by” should not be copied

Hi,

thanks for the plugin!

Just one thing: It doesn’t make sense for us to copy the field “_used_by” to the new coupon. I have removed this behaviour by adding the following code in line 195:

// Don’t copy the “_used_by” field
if ( ‘_used_by’ === $meta_key ) {
continue;
}

Would be cool if you can change this in the official plugin to help others ??

Thanks!