refactor(TabContent): remove obsolete react-lifecycles-compat

New lifecycle methods were introduced in [`react@16.3`][1]
`reactstrap` has listed minimal `react` supported version as `16.3`

[1]: https://reactjs.org/blog/2018/03/29/react-v-16-3.html

package.json

@@ -257,7 +257,6 @@
     "@babel/runtime": "^7.2.0",
     "classnames": "^2.2.3",
     "prop-types": "^15.5.8",
-    "react-lifecycles-compat": "^3.0.4",
     "react-popper": "^1.3.6",
     "react-transition-group": "^2.3.1"
   },

src/TabContent.js

@@ -1,5 +1,4 @@
 import React, { Component } from 'react';
-import { polyfill } from 'react-lifecycles-compat';
 import PropTypes from 'prop-types';
 import classNames from 'classnames';
 import { TabContext } from './TabContext';
@@ -53,7 +52,6 @@ class TabContent extends Component {
   }
 }
 
-polyfill(TabContent);
 export default TabContent;
 
 TabContent.propTypes = propTypes;