Move env var CONTAINER_IMAGE_REGISTRY to an optional input since GitH…

…ub Actions files do not support env vars.

.github/actions/clp-execution-image-build/action.yaml

@@ -3,20 +3,21 @@ description: "Builds a container image that contains the dependencies necessary
 to run the CLP package."
 
 inputs:
+  containerImageRegistry:
+    description: "Container Image Registry"
+    required: false
+    default: "ghcr.io"
   dockerfilePath:
     description: "Path to the Dockerfile."
     required: true
   platformId:
     description: "Platform ID of the container. e.g., ubuntu."
     required: true
   platformVersionId:
-    description: "Platform VERSION_ID / VERSION_CODENAME of the container. 
+    description: "Platform VERSION_ID / VERSION_CODENAME of the container.
       e.g., jammy, focal."
     required: true
 
-env:
-  CONTAINER_IMAGE_REGISTRY: "ghcr.io"
-
 runs:
   using: "composite"
   steps:
@@ -30,7 +31,7 @@ runs:
 
     - uses: "docker/login-action@v3"
       with:
-        registry: "${{env.CONTAINER_IMAGE_REGISTRY}}"
+        registry: "${{inputs.containerImageRegistry}}"
         username: "${{github.actor}}"
         password: "${{secrets.GITHUB_TOKEN}}"
 
@@ -45,7 +46,7 @@ runs:
     - id: "meta"
       uses: "docker/metadata-action@v5"
       with:
-        images: "${{env.CONTAINER_IMAGE_REGISTRY}}/${{steps.sanitization.outputs.REPOSITORY}}\
+        images: "${{inputs.containerImageRegistry}}/${{steps.sanitization.outputs.REPOSITORY}}\
           /clp-execution-x86-${{inputs.platformId}}-${{inputs.platformVersionId}}"
 
     - if: "github.event_name != 'pull_request' && github.ref == 'refs/heads/main'"