Vue.js for loop for to programmatically uncheck a check box

I wrote a js fiddle where I am trying to uncheck the last checkbox checked if more than 3 checkboxes have been checked. I tried setting the index to false, but that didn't work. I also tried pop, also didn't work.

Here is my code https://jsfiddle.net/aaronmk2/ums2jq1g/18/

new Vue({
  el: "#app",
  data: {
  counter: 0,
  temp: [],
    todos: [
      { text: "Learn JavaScript" },
      { text: "Learn Vue"},
      { text: "Play around in JSFiddle" },
      { text: "Build something awesome" }
    ]
  },
  methods: {
    toggle: function(todo){
    console.log(todo)
        todo.done = !todo.done
    },
    test:function(index){
      this.counter++;
      if(this.counter > 2){
        console.log("reset checkMar")
        this.temp[index] = false
      }
    },
  }
})