react/no-unused-prop-types cannot find props being used inside helper functions

```javascript

const showAlert = props => **props.status** === PENDING;

const Alert = (props) => {
  if (showAlert(props)) {
    return (
      <div />
    );
  }

  return <noscript/>;
};

Alert.propTypes = {
  **status**: PropTypes.oneOf([PENDING, ACCEPTED, CANCELED])
};
```

In this case `props.status` is being used inside of the function `showAlert`.