fix: upgrade react-hot-loader for example to work with latest React

- was getting a difficult-to-interpret error when running `npm start`
  - https://stackoverflow.com/q/40652327/3431180
  - fixed by upgrading react-hot-loader and updating the config
    accordingly

Author: agilgur5

package-lock.json

@@ -74,7 +74,7 @@
     "jest-without-globals": "^0.0.2",
     "react": "^17.0.2",
     "react-dom": "^17.0.2",
-    "react-hot-loader": "^1.2.7",
+    "react-hot-loader": "^4.13.0",
     "standard": "^13.0.2",
     "style-loader": "^0.13.1",
     "webpack": "^1.12.2",

package.json

@@ -15,8 +15,10 @@ module.exports = {
       test: /\.js$/,
       exclude: /node_modules/,
       loaders: [
-        'react-hot',
-        query('babel-loader', { presets: ['es2015', 'react', 'stage-2'] })
+        query('babel-loader', {
+          presets: ['es2015', 'react', 'stage-2'],
+          plugins: ['react-hot-loader/babel']
+        })
       ]
     }, {
       test: /\.cssm$/, loader: 'style-loader!css-loader?modules'