Bump webpack-dev-server from 2.11.3 to 3.1.11 in /webpack3

Bumps [webpack-dev-server](https://github.com/webpack/webpack-dev-server) from 2.11.3 to 3.1.11.
- [Release notes](https://github.com/webpack/webpack-dev-server/releases)
- [Changelog](https://github.com/webpack/webpack-dev-server/blob/master/CHANGELOG.md)
- [Commits](webpack/webpack-dev-server@v2.11.3...v3.1.11)

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

webpack3/package.json

@@ -9,6 +9,6 @@
     "html-webpack-plugin": "^2.30.1",
     "ts-loader": "^2.3.4",
     "webpack": "^3.5.5",
-    "webpack-dev-server": "^2.7.1"
+    "webpack-dev-server": "^3.1.11"
   }
 }