Fix Heruko buildpacks samples

Ref: heroku/buildpacks-procfile#214
Ref: heroku/libcnb.rs@033f612

Add `CNB_TARGET_OS` and `CNB_TARGET_ARCH` to fix error during the detect
phase, where the target system cannot be detected:
```
[Error: Internal Buildpack Error]
Couldn't determine target os: environment variable not found
err:  heroku/[email protected] (1)
======== Output: heroku/[email protected] ========
```

There seems to be a changed behavior that was introduced in the common
buildpacks library that is in use that expects these environment
variables to be present to detect the target system OS and architecture.

Signed-off-by: Matthias Diester <[email protected]>

samples/v1alpha1/buildstrategy/buildpacks-v3/buildstrategy_buildpacks-v3-heroku_cr.yaml

@@ -8,13 +8,23 @@ spec:
     - name: platform-env
       emptyDir: {}
   parameters:
+    - name: operating-system
+      description: The target operating system for the buildpacks build.
+      default: "linux"
+    - name: system-architecture
+      description: The target system architecture for the buildpacks build.
+      default: "x86_64"
     - name: platform-api-version
       description: The referenced version is the minimum version that all relevant buildpack implementations support.
       default: "0.7"
   buildSteps:
     - name: build-and-push
       image: heroku/builder:22
       env:
+        - name: CNB_TARGET_OS
+          value: $(params.operating-system)
+        - name: CNB_TARGET_ARCH
+          value: $(params.system-architecture)
         - name: CNB_PLATFORM_API
           value: $(params.platform-api-version)
         - name: PARAM_SOURCE_CONTEXT
@@ -62,7 +72,7 @@ spec:
           mkdir -p "$CACHE_DIR" "$LAYERS_DIR"
 
           function announce_phase {
-            printf "===> %s\n" "$1" 
+            printf "===> %s\n" "$1"
           }
 
           announce_phase "ANALYZING"

samples/v1alpha1/buildstrategy/buildpacks-v3/buildstrategy_buildpacks-v3-heroku_namespaced_cr.yaml

@@ -8,13 +8,23 @@ spec:
     - name: platform-env
       emptyDir: {}
   parameters:
+    - name: operating-system
+      description: The target operating system for the buildpacks build.
+      default: "linux"
+    - name: system-architecture
+      description: The target system architecture for the buildpacks build.
+      default: "x86_64"
     - name: platform-api-version
       description: The referenced version is the minimum version that all relevant buildpack implementations support.
       default: "0.7"
   buildSteps:
     - name: build-and-push
       image: heroku/builder:22
       env:
+        - name: CNB_TARGET_OS
+          value: $(params.operating-system)
+        - name: CNB_TARGET_ARCH
+          value: $(params.system-architecture)
         - name: CNB_PLATFORM_API
           value: $(params.platform-api-version)
         - name: PARAM_SOURCE_CONTEXT

samples/v1beta1/buildstrategy/buildpacks-v3/buildstrategy_buildpacks-v3-heroku_cr.yaml

@@ -8,13 +8,23 @@ spec:
     - name: platform-env
       emptyDir: {}
   parameters:
+    - name: operating-system
+      description: The target operating system for the buildpacks build.
+      default: "linux"
+    - name: system-architecture
+      description: The target system architecture for the buildpacks build.
+      default: "x86_64"
     - name: platform-api-version
       description: The referenced version is the minimum version that all relevant buildpack implementations support.
       default: "0.7"
   steps:
     - name: build-and-push
       image: heroku/builder:22
       env:
+        - name: CNB_TARGET_OS
+          value: $(params.operating-system)
+        - name: CNB_TARGET_ARCH
+          value: $(params.system-architecture)
         - name: CNB_PLATFORM_API
           value: $(params.platform-api-version)
         - name: PARAM_SOURCE_CONTEXT
@@ -62,7 +72,7 @@ spec:
           mkdir -p "$CACHE_DIR" "$LAYERS_DIR"
 
           function announce_phase {
-            printf "===> %s\n" "$1" 
+            printf "===> %s\n" "$1"
           }
 
           announce_phase "ANALYZING"

samples/v1beta1/buildstrategy/buildpacks-v3/buildstrategy_buildpacks-v3-heroku_namespaced_cr.yaml

@@ -8,13 +8,23 @@ spec:
     - name: platform-env
       emptyDir: {}
   parameters:
+    - name: operating-system
+      description: The target operating system for the buildpacks build.
+      default: "linux"
+    - name: system-architecture
+      description: The target system architecture for the buildpacks build.
+      default: "x86_64"
     - name: platform-api-version
       description: The referenced version is the minimum version that all relevant buildpack implementations support.
       default: "0.7"
   steps:
     - name: build-and-push
       image: heroku/builder:22
       env:
+        - name: CNB_TARGET_OS
+          value: $(params.operating-system)
+        - name: CNB_TARGET_ARCH
+          value: $(params.system-architecture)
         - name: CNB_PLATFORM_API
           value: $(params.platform-api-version)
         - name: PARAM_SOURCE_CONTEXT