Update Next.js, Material UI

admin/next.config.js

@@ -1,7 +1,10 @@
-const withCSS = require("@zeit/next-css");
-const MonacoWebpackPlugin = require("monaco-editor-webpack-plugin");
+// @ts-check
 
-module.exports = withCSS({
+/**
+ * @type {import('next').NextConfig}
+ **/
+const nextConfig = {
+  reactStrictMode: true,
   trailingSlash: true,
   async rewrites() {
     return [
@@ -11,24 +14,6 @@ module.exports = withCSS({
       },
     ];
   },
-  webpack: (config) => {
-    config.module.rules.push({
-      test: /\.(png|jpg|gif|svg|eot|ttf|woff|woff2)$/,
-      use: {
-        loader: "url-loader",
-        options: {
-          limit: 100000,
-        },
-      },
-    });
+};
 
-    config.plugins.push(
-      new MonacoWebpackPlugin({
-        languages: ["html", "json", "javascript"],
-        filename: "static/[name].worker.js",
-      })
-    );
-
-    return config;
-  },
-});
+module.exports = nextConfig;