fix: reorder steps in Docker workflow and update image reference for Trivy scan

Author: milsman2

.github/workflows/docker-build-and-scan.yaml

@@ -14,10 +14,12 @@ jobs:
       DOCKER_LOAD: true
       TAGS: sample-python-app:${{ github.sha }}
     steps:
-      - name: Set up Docker Buildx
-        uses: docker/setup-buildx-action@v3.12.0
+      - name: Checkout repository
+        uses: actions/checkout@v6
       - name: Set up QEMU
         uses: docker/setup-qemu-action@v3.7.0
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v3.12.0
       - name: Build Docker Image
         id: build-image
         uses: docker/build-push-action@v6
@@ -29,7 +31,7 @@ jobs:
       - name: Run Trivy vulnerability scanner
         uses: aquasecurity/trivy-action@0.33.1
         with:
-          image-ref: ${{ steps.build-image.outputs.digest }}
+          image-ref: ${{ env.TAGS }}
           format: 'table'
           exit-code: '1'
           ignore-unfixed: true