fix prop-types problem

website/core/Footer.js

@@ -1,6 +1,7 @@
 "use strict";
 
 const React = require("react");
+const PropTypes = require("prop-types");
 
 const GithubButton = props => (
   <a
@@ -14,6 +15,10 @@ const GithubButton = props => (
   </a>
 );
 
+GithubButton.propTypes = {
+  config: PropTypes.object
+};
+
 class Footer extends React.Component {
   url(path) {
     const language = this.props.language || "en";
@@ -79,4 +84,9 @@ class Footer extends React.Component {
   }
 }
 
+Footer.propTypes = {
+  language: PropTypes.string,
+  config: PropTypes.object
+};
+
 module.exports = Footer;

website/package.json

@@ -10,6 +10,7 @@
   "dependencies": {
     "codemirror": "5.36.0",
     "lz-string": "1.4.4",
+    "prop-types": "15.6.1",
     "react": "16.3.1",
     "react-dom": "16.3.1",
     "sw-toolbox": "3.6.0"

website/yarn.lock

@@ -4161,6 +4161,14 @@ promise@^7.1.1:
   dependencies:
     asap "~2.0.3"
 
+prop-types@15.6.1:
+  version "15.6.1"
+  resolved "https://registry.yarnpkg.com/prop-types/-/prop-types-15.6.1.tgz#36644453564255ddda391191fb3a125cbdf654ca"
+  dependencies:
+    fbjs "^0.8.16"
+    loose-envify "^1.3.1"
+    object-assign "^4.1.1"
+
 prop-types@^15.5.10:
   version "15.5.10"
   resolved "https://registry.yarnpkg.com/prop-types/-/prop-types-15.5.10.tgz#2797dfc3126182e3a95e3dfbb2e893ddd7456154"