Merge pull request #1048 from reactjs/dependabot/npm_and_yarn/test/dummy_sprockets/webpack-dev-server-3.1.11

Bump webpack-dev-server from 2.11.5 to 3.1.11 in /test/dummy_sprockets

Author: BookOfGreg

test/dummy_sprockets/package.json

@@ -32,6 +32,6 @@
     "webpack-merge": "^4.1.0"
   },
   "devDependencies": {
-    "webpack-dev-server": "^2.4.5"
+    "webpack-dev-server": "^3.1.11"
   }
 }