Fire event on Change not on Click with dropdown!

When we wire the postback event to click, it will fire with the user's initial click on the dropdown, not when he has selected an item(which is what the dropdown is for).

src/elements/element_dropdown.erl

@@ -6,7 +6,7 @@ render_element(Record = #dropdown{}) ->
     ID = case Record#dropdown.id of undefined -> nitro:temp_id(); I->I end,
     case Record#dropdown.postback of
          undefined -> skip;
-         Postback -> nitro:wire(#event { type=click, postback=Postback, target=ID,
+         Postback -> nitro:wire(#event { type=change, postback=Postback, target=ID,
                         source=Record#dropdown.source, delegate=Record#dropdown.delegate } ) end,
 
     Opts = [wf_tags:emit_tag(<<"option">>, [O#option.label], [