[Security] Bump webpack-dev-server from 3.1.3 to 3.1.14

Bumps [webpack-dev-server](https://github.com/webpack/webpack-dev-server) from 3.1.3 to 3.1.14. **This update includes security fixes.**
- [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@v3.1.3...v3.1.14)

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

package.json

@@ -108,7 +108,7 @@
     "typescript": "^3.1.6",
     "webpack": "^4.3.0",
     "webpack-cli": "^2.0.13",
-    "webpack-dev-server": "^3.1.1",
+    "webpack-dev-server": "^3.1.14",
     "webpackbar": "^2.6.1"
   }
 }