Import lottie_light to reduce bundle size.

AFAICT react-lottie always uses the svg renderer and
(at least in my case) the animations don't have expressions.

By importing the light version of of lottie-web one can save around
100KB (minified).

airbnb/lottie-web#929

src/index.js

@@ -1,6 +1,6 @@
 import React from 'react';
 import PropTypes from 'prop-types';
-import lottie from 'lottie-web';
+import lottie from 'lottie-web/build/player/lottie_light';
 
 export default class Lottie extends React.Component {
   componentDidMount() {