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

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]

backstage/yarn.lock

@@ -17178,9 +17178,9 @@ http-proxy-agent@^7.0.0:
     debug "^4.3.4"
 
 http-proxy-middleware@^2.0.0, http-proxy-middleware@^2.0.3, http-proxy-middleware@^2.0.6:
-  version "2.0.7"
-  resolved "https://registry.yarnpkg.com/http-proxy-middleware/-/http-proxy-middleware-2.0.7.tgz#915f236d92ae98ef48278a95dedf17e991936ec6"
-  integrity sha512-fgVY8AV7qU7z/MmXJ/rxwbrtQH4jBQ9m7kp3llF0liB7glmFeVZFBepQb32T3y8n8k2+AEYuMPCpinYW+/CuRA==
+  version "2.0.9"
+  resolved "https://registry.yarnpkg.com/http-proxy-middleware/-/http-proxy-middleware-2.0.9.tgz#e9e63d68afaa4eee3d147f39149ab84c0c2815ef"
+  integrity sha512-c1IyJYLYppU574+YI7R4QyX2ystMtVXZwIdzazUIPIJsHuWNd+mho2j+bKoHftndicGj9yh+xjd+l0yj7VeT1Q==
   dependencies:
     "@types/http-proxy" "^1.17.8"
     http-proxy "^1.18.1"