onClick event for follow button

[BaliBalo]

Lets people add an onClick property as a function to be called whenever the twitter button is clicked. Use cases: tracking, user feedback, etc.

I tried to follow the coding conventions of the repo, let me know if anything is incorrect.

[kgdiem]

@saurabhnemade Desperately need this functionality for my project

[kgdiem]

Scratch that! Just realized it is only for button!

~However, @BaliBalo , I installed your version from github and implemented like so, to no avail. The event is never called~

<TwitterTweetEmbed
        placeholder={<div className={classes.placeholder} />}
        tweetId={article.tweet}
        options={OPTIONS}
        onClick={(e) => onClick(e)}
/>

function onClick(event) {
    event.preventDefault();
    event.stopPropagation();

    console.log(event.target);
  }

"react-twitter-embed": "BaliBalo/react-twitter-embed#features/onClick-follow-button",

[BaliBalo]

Closing due to conflicts with new TypeScript code and lack of interest - if someone feels like it, feel free to port this code in a new PR