fix(webpack-dev-server): Fix check for webpack-dev-server version

Author: danez

tasks/webpack-dev-server.js

@@ -66,8 +66,8 @@ npm install --save-dev webpack-dev-server
     );
     return;
   }
-  if (WebpackDevServer.socketPath === undefined) {
-    // socketPath was introduced in version 3.2.0
+  if (WebpackDevServer.sockPath === undefined) {
+    // sockPath was introduced in version 3.2.0
     grunt.fail.fatal(
       `webpack-dev-server is outdated. Please ensure you have at least version 3.2.0 installed.`,
     );