Update .github/workflows/build.yaml

Co-authored-by: Copilot <[email protected]>

Author: mrrobot47

.github/workflows/build.yaml

@@ -20,6 +20,12 @@ jobs:
         uses: docker/setup-buildx-action@e468171a9de216ec08956ac3ada2f0791b6bd435 # v3.11.1
       - name: Login to GitHub Container Registry
         run: echo "${{ secrets.GITHUB_TOKEN }}" | docker login ghcr.io -u ${{ github.actor }} --password-stdin
+      - name: Set Lowercase Image Tag
+        id: prep
+        run: |
+          IMAGE_TAG="ghcr.io/${{ github.repository }}:${{ github.ref_name }}"
+          IMAGE_TAG_LOWER=$(echo "$IMAGE_TAG" | tr '[:upper:]' '[:lower:]')
+          echo "IMAGE_TAG_LOWER=$IMAGE_TAG_LOWER" >> $GITHUB_ENV
       - name: Build and Push Multi-Arch Docker Image
         run: |
-          docker buildx build --platform linux/amd64,linux/arm64 -t $(echo 'ghcr.io/${{ github.repository }}:${{ github.ref_name }}' | tr '[:upper:]' '[:lower:]') --push .
+          docker buildx build --platform linux/amd64,linux/arm64 -t "$IMAGE_TAG_LOWER" --push .