Update webpack-dev-server to 4.15.1

package.json

@@ -48,7 +48,7 @@
         "start": "yarn build:module_system && concurrently --kill-others-on-fail --prefix \"{time} [{name}]\" -n res,element-js \"yarn start:res\" \"yarn start:js\"",
         "start:https": "concurrently --kill-others-on-fail --prefix \"{time} [{name}]\" -n res,element-js \"yarn start:res\" \"yarn start:js --https\"",
         "start:res": "yarn build:jitsi && ts-node scripts/copy-res.ts -w",
-        "start:js": "webpack serve --output-path webapp --mode development --disable-host-check --hot",
+        "start:js": "webpack serve --output-path webapp --mode development",
         "lint": "yarn lint:types && yarn lint:js && yarn lint:style",
         "lint:js": "yarn lint:js:src && yarn lint:js:module_system",
         "lint:js:src": "eslint --max-warnings 0 src test && prettier --check .",
@@ -184,7 +184,7 @@
         "webpack": "^4.47.0",
         "webpack-bundle-analyzer": "^4.8.0",
         "webpack-cli": "^4.10.0",
-        "webpack-dev-server": "^3.11.2",
+        "webpack-dev-server": "^4.15.1",
         "worker-loader": "^3.0.0",
         "worklet-loader": "^2.0.0",
         "yaml": "^2.0.1"

webpack.config.js

@@ -728,14 +728,23 @@ module.exports = (env, argv) => {
 
         // configuration for the webpack-dev-server
         devServer: {
-            // serve unwebpacked assets from webapp.
-            contentBase: ["./webapp"],
+            static: {
+                // Where to serve static assets from
+                directory: "./webapp",
+            },
 
+            devMiddleware: {
                 // Only output errors, warnings, or new compilations.
                 // This hides the massive list of modules.
                 stats: "minimal",
-            hotOnly: true,
-            inline: true,
+            },
+
+            // Enable Hot Module Replacement without page refresh as a fallback in
+            // case of build failures
+            hot: "only",
+
+            // Disable host check
+            allowedHosts: 'all',
         },
     };
 };