title: Shouldn't Eslint enforce props fields to be readonly in React?
body: <p>Say I have the following code snippet:</p>
  
  <pre><code>interface MyProps {
    label: string;
  }
  
  function MyComponent(props: MyProps) {
    return (
      &lt;p&gt;
        {props.label}
      &lt;/p&gt;
    );
  }
  </code></pre>
  
  <p>Neither Eslint nor the TypeScript compiler throws a warning or an error if I don't mark the fields in <code>Props</code> as <code>readonly</code>. Yet, component props should never be modified, otherwise the React UI engine won't work as expected.</p>
  
  <p>This is with Eslint@6.8.0, React@16.13.1 and TypeScript@3.9.3.</p>