Bump http-proxy-middleware from 2.0.7 to 2.0.9 in /docs

Bumps [http-proxy-middleware](https://github.com/chimurai/http-proxy-middleware) from 2.0.7 to 2.0.9.
- [Release notes](https://github.com/chimurai/http-proxy-middleware/releases)
- [Changelog](https://github.com/chimurai/http-proxy-middleware/blob/v2.0.9/CHANGELOG.md)
- [Commits](chimurai/http-proxy-middleware@v2.0.7...v2.0.9)

---
updated-dependencies:
- dependency-name: http-proxy-middleware
  dependency-version: 2.0.9
  dependency-type: indirect
...

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

Author: dependabot[bot]