With Glimmer any attributes intended to go onto the <select> are handled by a ...attributes, custom functionality is handled as a passed in property.
This means that standard attributes such as disabled, id, class can be used like so...
Meanwhile, @placeholder, @options, @value, @placeholder, @valueKey, and @displayKey must be prefixed with an @ to specify properties we're passing to the component (rather than an attribute passed to the select element).