ie11 not supporting Object.is

[sakuraNouta]

It using in file composition-api/src/apis/watch.ts
reference https://developer.mozilla.org/zh-CN/docs/Web/JavaScript/Reference/Global_Objects/Object/is

 const applyCb = (n: any, o: any) => {
    if (
      !deep &&
      isMultiSource &&
      n.every((v: any, i: number) => Object.is(v, o[i]))
    )
      return
    // cleanup before running cb again
    runCleanup()
    return cb(n, o, registerCleanup)
  }

[Anthony Fu]

PR welcome