v1.2.1

We've fixed a bug where using pure components under the <Elements> component
would lead to an error.

For example, this used to raise an error but does not anymore:

class PureWrapper extends React.PureComponent {
  render() {
    return <div>{this.props.children}</div>;
  }
}

// ...

    <StripeProvider apiKey='pk_test_foo123'>
      <Elements>
        <PureWrapper>
          <InjectedCheckoutForm />
        </PureWrapper>
      </Elements>
    </StripeProvider>