Adding webpack fast refresh support.

package.json

@@ -25,6 +25,7 @@
     "@babel/plugin-proposal-decorators": "^7.8.3",
     "@babel/preset-env": "^7.8.3",
     "@babel/preset-react": "^7.8.3",
+    "@pmmmwh/react-refresh-webpack-plugin": "^0.4.1",
     "autoprefixer": "^9.7.4",
     "babel-loader": "^8.0.6",
     "babel-plugin-transform-decorators-legacy": "^1.3.5",
@@ -40,6 +41,7 @@
     "node-sass": "^4.13.1",
     "optimize-css-assets-webpack-plugin": "^5.0.3",
     "postcss-loader": "^3.0.0",
+    "react-refresh": "^0.8.3",
     "sass-loader": "^8.0.2",
     "style-loader": "^1.1.3",
     "terser-webpack-plugin": "^2.3.5",