Add digest output to action.yml and set build-and-push step ID

This update introduces a new output 'digest' to the action.yml file, which captures the digest value from the build-and-push step. Additionally, the build-and-push step is now assigned an ID for better output management.

action.yml

@@ -30,6 +30,9 @@ inputs:
     description: "Build Secrets"
 
 outputs:
+  digest:
+    description: "Digest"
+    value: ${{ steps.build-and-push.outputs.digest }}
   tag:
     description: "Image Tag"
     value: ${{ steps.set_tag.outputs.tag }}
@@ -71,6 +74,7 @@ runs:
 
     - name: Build Docker images
       uses: docker/build-push-action@v6
+      id: build-and-push
       with:
         push: ${{ inputs.push }}
         file: ${{ inputs.file }}