chore: update outbound-http crate deps

[booklearner]

Updates the outbound-http crate to use wasi-experimental-http-wasmtime release (0.9.0) instead of a specific revision.

Context: I'm packaging spin on nixpkgs, which relies on Cargo vendor to succeed. Running cargo vendor currently yields an error:

Caused by:
  found duplicate version of package `wasi-experimental-http-wasmtime v0.9.0` vendored from two sources:

      source 1: registry `crates-io`
      source 2: https://github.com/deislabs/wasi-experimental-http?rev=9a143fa7d8be2a66d6d636c5c1b0c6e2bad68912#9a143fa7

This PR should fix that!

[radu-matei]

Thanks a lot for catching this, @booklearner!
We need to create a new release for the HTTP repo to have deislabs/wasi-experimental-http#91, which Spin currently depends on.

Once we merge it, could you update this PR to point to 0.10.0, please?

Thank you so much!

[endocrimes]

It looks like https://crates.io/crates/wasi-experimental-http-wasmtime/0.10.0 has been released - @booklearner lemme know if you don't have time and I can carry this forwards (I ran into the same when trying to package spin 😅).

[booklearner]

Oh. Great! Thanks for the ping. I'll fix this up when I'm near my computer again soon

[booklearner]

It looks like the dependency was already updated in #574, I'm going to close this PR and push up changes to NixOS/nixpkgs#173444