Update rollup to fix bundle size regression

[emmatown]

What:

Some unnecessary babel helpers were in the output of 9.2.0

var _sPO = Object.setPrototypeOf || function _sPO(o, p) {
  o.__proto__ = p;
  return o;
};

var _construct = typeof Reflect === "object" && Reflect.construct || function _construct(Parent, args, Class) {
  var Constructor,
      a = [null];
  a.push.apply(a, args);
  Constructor = Parent.bind.apply(Parent, a);
  return _sPO(new Constructor(), Class.prototype);
};

Updating rollup seems to fix this.

Why:

How:

Checklist:

• Documentation N/A
• Tests N/A
• Code complete