chore(examples): Update Spin Rust SDK and other dependencies

[tschneidereit]

The Rust examples were all using Spin SDK 2.2.0, which targets a release candidate of WASIp2, not the final version. That means they only ran in Spin, not other WASI runtimes such as Wasmtime.

This commit updates all applicable examples to the latest Spin SDK and changes the build target to wasm32-wasip2 to directly build components.

Fixes #3275

[fibonacci1729]

Closing #3258 in favor of this one.

Also, would you mind updating gh workflows (build.yml and release.yml) to use the wasm32-wasip2 target?

[fibonacci1729]

Once the gh workflows are updated and the comment about missing export! is addressed the tests should pass and this looks good to me!

[ThorstenHans]

This is great!

With the samples compiling to wasm32-wasip2, I guess we would also want to update all the templates and spin doctor?

If so, I'm happy to help - especially with the templates. For spin doctor I see two ways of addressing this:

• we could flag manifests that have wasm32-wasip1 as target for Rust components and check if the wasm32-wasip2 target is installed
• we could report a suggestion and ask users to manually update the target in their build instructions and keep on checking for both Rust targets installed (maybe we're hitting cases where auto-upgrading from p1 to p2 could result in errors)

[tschneidereit]

I guess we would also want to update all the templates and spin doctor?

I think updating the templates makes sense, yes. Brian's #3258 (which I had missed—apologies!) did that, though I think there were a few more parts of the templates that need updating.

I'm less sure about spin doctor: there's not necessarily anything really wrong with targeting wasip1, and for now that's the only way to use Wizer. (That latter part will soon change, though.)