update todomvc with new key filter syntax

Author: yyx990803

examples/todomvc/index.html

@@ -14,7 +14,7 @@ <h1>todos</h1>
 					autofocus autocomplete="off"
 					placeholder="What needs to be done?"
 					v-model="newTodo"
-					on-keyup="addTodo | key 'enter'">
+					on-keyup:enter="addTodo">
 			</header>
 			<section class="main" v-show="todos.length" v-cloak>
 				<input class="toggle-all" type="checkbox" v-model="allDone">