Bump webpack-dev-server from 3.1.9 to 3.1.11

Bumps [webpack-dev-server](https://github.com/webpack/webpack-dev-server) from 3.1.9 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@v3.1.9...v3.1.11)

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

package.json

@@ -30,7 +30,7 @@
     "style-loader": "^0.23.0",
     "webpack": "^4.20.2",
     "webpack-cli": "^3.1.2",
-    "webpack-dev-server": "^3.1.9",
+    "webpack-dev-server": "^3.1.11",
     "webpack-merge": "^4.1.4"
   }
 }