updating workload file to use slight-rust-hello's v0.3.3 instead of latest

While trying to build today, we realized `latest` was broken. To avoid any other users running into this issue, it's best to target a specific version that was tested and is guaranteed to provide a great OOB experience in this tutorial.

Author: danbugs

articles/aks/use-wasi-node-pools.md

@@ -169,7 +169,7 @@ spec:
       runtimeClassName: wasmtime-slight-v1
       containers:
         - name: hello-slight
-          image: ghcr.io/deislabs/containerd-wasm-shims/examples/slight-rust-hello:latest
+          image: ghcr.io/deislabs/containerd-wasm-shims/examples/slight-rust-hello:v0.3.3
           command: ["/"]
           resources:
             requests: