Rendering React Components with HTML content?
Hi! I am... : reporting a bug or issue

I've was testing react-sketchapp which looks pretty neat so far!
Besides rendering the default sketch elements like `Text`,`View`,`Image` and so on, would it be possible to render a default react component containing HTML-Markup styled with css?

**Expected behavior:**
It should render a default react component with html elements.

**Observed behavior:**
`Could not find renderer for type 'span' flexToSketchJSON`

**How to reproduce:**
Try to render following Artboard: 

    import React from 'react';
    import { render, Artboard, Text, View } from 'react-sketchapp';
    
    const Hello = () => (
      <View
        name={`Hello View`}
      >
        <Text name="Hello Text">
          <span>Hello World</span>
        </Text>
      </View>
    );
    
    const Document = () => (
      <Artboard
        name="Hello Board"
      >
        <Hello />
      </Artboard>
    );
    
    export default (context) => {
      render(<Document />, context.document.currentPage());
    }

**Sketch version:** 43.2

