Refactor translate.js

The variable has not been reassigned a value, so it's better to use "const" instead of "let", to prevent any unexpected behavior that may occur due to unintended assignment.

src/components/translate.js

@@ -9,7 +9,7 @@ export default function (Glide, Components, Events) {
      * @return {Void}
      */
     set (value) {
-      let transform = mutator(Glide, Components).mutate(value)
+      const transform = mutator(Glide, Components).mutate(value)
       const translate3d = `translate3d(${-1 * transform}px, 0px, 0px)`
 
       Components.Html.wrapper.style.mozTransform = translate3d // needed for supported Firefox 10-15