How can I make use of Error boundaries in functional React components?

As of v16.2.0, there’s no way to turn a functional component into an error boundary.

The React docs are clear about that, although you’re free to reuse them as many times as you wish:

The componentDidCatch() method works like a JavaScript catch {} block, but for components. Only class components can be error boundaries. In practice, most of the time you’ll want to declare an error boundary component once and use it throughout your application.

Also bear in mind that try/catch blocks won’t work on all cases.
If a component deep in the hierarchy tries to updates and fails, the try/catch block in one of the parents won’t work — because it isn’t necessarily updating together with the child.