When setting boolean attributes on Web Components
`<x-search somebool name={this.props.name} />`
they get rendered as attribute/value pairs instead
`<x-search somebool="true" name={this.props.name}>`

This causes problems with some AMP components, for eg. `<amp-iframe />` which has a `resizable` attribute that gets rendered as `resizable="true"`. This results in non valid AMP content and developers crying with blood tears on their keyboards :)
> The attribute 'resizable' in tag 'amp-iframe' is set to the invalid value 'true'. (see https://www.ampproject.org/docs/reference/components/amp-iframe)

Is there any reason for the current behaviour? Will changing this break something else?
customelement.dispatchEvent(new Event('customevent'));
      expect(oncustomevent).toHaveBeenCalledTimes(0);
      expect(customelement.oncustomevent).toBe(undefined);
      expect(customelement.getAttribute('oncustomevent')).toBe('foo');
      
      ReactDOM.render(
        <my-custom-element oncustomevent={oncustomevent} />,
        container,
      );
      customelement.dispatchEvent(new Event('customevent'));
      expect(oncustomevent).toHaveBeenCalledTimes(1);
      expect(customelement.oncustomevent).toBe(undefined);
      expect(customelement.getAttribute('oncustomevent')).toBe(null);
      
      ReactDOM.render(<my-custom-element oncustomevent={'foo'} />, container);
      customelement.dispatchEvent(new Event('customevent'));
      expect(oncustomevent).toHaveBeenCalledTimes(1);
      expect(customelement.oncustomevent).toBe(undefined);
      expect(customelement.getAttribute('oncustomevent')).toBe('foo');
      
      ReactDOM.render(<my-custom-element />, container);
      customelement.dispatchEvent(new Event('customevent'));
      expect(oncustomevent).toHaveBeenCalledTimes(1);
      expect(customelement.oncustomevent).toBe(undefined);
      expect(customelement.getAttribute('oncustomevent')).toBe(null);
      
      ReactDOM.render(
        <my-custom-element oncustomevent={oncustomevent} />,
        container,
      );