fix invalid cache image tag name

Author: lovasoa

.github/workflows/ci.yml

@@ -83,6 +83,8 @@ jobs:
         with:
           username: ${{ env.REGISTRY_USERNAME }}
           password: ${{ secrets.DOCKERHUB_TOKEN }}
+      - id: cache_name
+        run: echo "img=${{ env.REGISTRY_IMAGE }}:cache-$(tr '/' '-' <<< ${{ matrix.platform }})" >> "$GITHUB_OUTPUT"
       - name: Build and push by digest
         id: build
         uses: docker/build-push-action@v5
@@ -91,8 +93,8 @@ jobs:
           platforms: ${{ matrix.platform }}
           labels: ${{ steps.meta.outputs.labels }}
           outputs: type=image,name=${{ env.REGISTRY_IMAGE }},push-by-digest=true,name-canonical=true,push=true
-          cache-from: type=registry,ref=${{ env.REGISTRY_IMAGE }}:cache-${{ matrix.platform }}
-          cache-to: type=registry,ref=${{ env.REGISTRY_IMAGE }}:cache-${{ matrix.platform }},compression=zstd,mode=max
+          cache-from: type=registry,ref=${{ steps.cache_name.outputs.img }}
+          cache-to: type=registry,ref=${{ steps.cache_name.outputs.img }},compression=zstd,mode=max
       - name: Export digest
         run: |
           mkdir -p /tmp/digests