fix(limel-chip-set): change name of method focus to setFocus

`focus` is a reserved public name on HTML elements.

BREAKING CHANGE: The method `focus()` on `limel-chip-set` has been renamed to `setFocus()`.

src/components/chip-set/chip-set.tsx

@@ -94,8 +94,13 @@ export class ChipSet {
         this.handleTextInput = this.handleTextInput.bind(this);
     }
 
+    /**
+     * Used to set focus to the chip-set input field.
+     *
+     * @returns {void}
+     */
     @Method()
-    public focus() {
+    public setFocus() {
         this.editMode = true;
         this.host.shadowRoot.querySelector('input').focus();
     }

src/components/picker/picker.tsx

@@ -109,7 +109,7 @@ export class Picker {
         }
 
         const chipSet = this.element.shadowRoot.querySelector('limel-chip-set');
-        chipSet.focus();
+        chipSet.setFocus();
     }
 
     public componentDidLoad() {