chore: fix warning util._extend during dev start

[JannikStreek]

Describe the bug
When starting the dev server, I get this:

(node:77) [DEP0060] DeprecationWarning: The `util._extend` API is deprecated. Please use Object.assign() instead.

which might be coming from the http_proxy package.

For more details and a possible solution see vitejs/vite#16655

[JannikStreek]

closing this for now as this is a problem of the proxy npm package.