Bump webpack-dev-server from 3.1.11 to 5.2.1

Bumps [webpack-dev-server](https://github.com/webpack/webpack-dev-server) from 3.1.11 to 5.2.1.
- [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@v3.1.11...v5.2.1)

---
updated-dependencies:
- dependency-name: webpack-dev-server
  dependency-version: 5.2.1
  dependency-type: direct:production
...

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

Author: dependabot[bot]

package.json

@@ -25,7 +25,7 @@
     "typescript": "~2.7.1",
     "url-loader": "~0.6.2",
     "webpack": "~3.10.0",
-    "webpack-dev-server": "3.1.11"
+    "webpack-dev-server": "5.2.1"
   }
 
 }