add example of render prop technique

[marcelmokos]

Add component with styled components in defaultProps

• There are two articles where I was focusing on a technique that uses render props together with React defaultProps to create fully customizable components that enable to customize every subcomponent as well.
• both articles have examples in codesandbox and I prefer to attach an article with an example that has a link to an in-depth one.

In-depth article: https://medium.com/ableneo/improve-how-you-style-react-apps-use-components-in-defaultprops-a8fd59e875d7

Article with an example: https://medium.com/ableneo/example-of-a-component-with-styled-components-in-defaultprops-612c0f5ac386

I hope you will like my contribution. Thanks for adding my article in, or for any valuable feedback.