chore: upgrade webpack-dev-server to 3.4.1 (#4020)

fixes #4016

(cherry picked from commit fa7c1aa)

Author: Payton Burdette

packages/@vue/cli-service/package.json

@@ -76,7 +76,7 @@
     "webpack": ">=4 < 4.29",
     "webpack-bundle-analyzer": "^3.3.0",
     "webpack-chain": "^4.11.0",
-    "webpack-dev-server": "^3.3.1",
+    "webpack-dev-server": "^3.4.1",
     "webpack-merge": "^4.2.1",
     "yorkie": "^2.0.0"
   },