Use prop-types library to silence PropTypes deprecation warning (#2498)

* Use prop-types library to fix the deprecation warning.

* Updated weaveworks-ui-components version.

client/app/scripts/components/cloud-feature.js

@@ -1,4 +1,5 @@
 import React from 'react';
+import PropTypes from 'prop-types';
 import { connect } from 'react-redux';
 
 class CloudFeature extends React.Component {
@@ -21,14 +22,14 @@ class CloudFeature extends React.Component {
 }
 
 CloudFeature.contextTypes = {
-  store: React.PropTypes.object.isRequired,
-  router: React.PropTypes.object,
-  serviceStore: React.PropTypes.object
+  store: PropTypes.object.isRequired,
+  router: PropTypes.object,
+  serviceStore: PropTypes.object
 };
 
 CloudFeature.childContextTypes = {
-  store: React.PropTypes.object,
-  router: React.PropTypes.object
+  store: PropTypes.object,
+  router: PropTypes.object
 };
 
 export default connect()(CloudFeature);

client/app/scripts/components/sparkline.js

@@ -1,5 +1,6 @@
 // Forked from: https://github.com/KyleAMathews/react-sparkline at commit a9d7c5203d8f240938b9f2288287aaf0478df013
 import React from 'react';
+import PropTypes from 'prop-types';
 import { min as d3Min, max as d3Max, mean as d3Mean } from 'd3-array';
 import { isoParse as parseDate } from 'd3-time-format';
 import { line, curveLinear } from 'd3-shape';
@@ -9,9 +10,9 @@ import { formatMetricSvg } from '../utils/string-utils';
 
 
 export default class Sparkline extends React.Component {
-
   constructor(props, context) {
     super(props, context);
+
     this.x = scaleLinear();
     this.y = scaleLinear();
     this.line = line()
@@ -96,7 +97,7 @@ export default class Sparkline extends React.Component {
 }
 
 Sparkline.propTypes = {
-  data: React.PropTypes.arrayOf(React.PropTypes.object)
+  data: PropTypes.arrayOf(PropTypes.object)
 };
 
 Sparkline.defaultProps = {