Create a new method called "toggleMultiple()"

[joaovitor-correa]

It would be interesting, and in my case very useful, if there was a method called toggleMultiple() that dynamically updated the multiple property.

The use of the method could be something like:

/** enable multi-select */
document.querySelector('#sample-select').toggleMultiple(true);

/** disable multi-select */
document.querySelector('#sample-select').toggleMultiple(false);