Update README

README.md

@@ -13,7 +13,7 @@
 It is an opinionated implementation adding language constructs and convenience methods for working
 with the spec. It values strong adherence to the spec and data formats.
 
-It currently targets version `0.9` of the CNB [Buildpack API specification](https://github.com/buildpacks/spec/blob/buildpack/0.9/buildpack.md).
+It currently targets version `0.10` of the CNB [Buildpack API specification](https://github.com/buildpacks/spec/blob/buildpack/0.9/buildpack.md).
 
 ## Quick Start Guide
 
@@ -85,8 +85,9 @@ id = "libcnb-examples/my-buildpack"
 version = "0.1.0"
 name = "My Buildpack"
 
-[[stacks]]
-id = "*"
+[[targets]]
+os = "linux"
+arch = "amd64"
 ```
 
 That's all we need! We can now move on to finally write some buildpack code!
@@ -132,7 +133,7 @@ impl Buildpack for HelloWorldBuildpack {
     type Error = GenericError;
 
     // This method will be called when the CNB lifecycle executes the detect phase (`bin/detect`).
-    // Use the `DetectContext` to access CNB data such as the stack this buildpack is currently
+    // Use the `DetectContext` to access CNB data such as the operating system this buildpack is currently
     // executed on, the app directory and similar things. When using libcnb.rs, you never have
     // to read environment variables or read/write files to disk to interact with the CNB lifecycle.
     //
@@ -148,6 +149,7 @@ impl Buildpack for HelloWorldBuildpack {
     // build phase (`bin/build`).
     fn build(&self, context: BuildContext<Self>) -> libcnb::Result<BuildResult, Self::Error> {
         println!("Hello World!");
+        println!("Build runs on: {} ({})!", context.target_os, context.target_arch);
 
         BuildResultBuilder::new()
             .launch(