setup qemu later + matrix steps

.github/workflows/build.yml

@@ -12,18 +12,28 @@ env:
 jobs:
   build-and-push-image:
     runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        platform:
+          - linux/amd64
+          - linux/arm/v6
+          - linux/arm/v7
+          - linux/arm64
 
     permissions:
       contents: read
       packages: write
 
     steps:
+      - name: Prepare
+        run: |
+          platform=${{ matrix.platform }}
+          echo "PLATFORM_PAIR=${platform//\//-}" >> $GITHUB_ENV
+
       - name: Checkout repository
         uses: actions/checkout@v3
 
-      - name: Set up QEMU
-        uses: docker/setup-qemu-action@v3
-
       - name: Log in to the Container registry
         uses: docker/login-action@v3
         with:
@@ -37,6 +47,9 @@ jobs:
         with:
           images: ${{ env.REGISTRY }}/${{ env.IMAGE_AUTHOR }}/${{ env.IMAGE_NAME }}
 
+      - name: Set up QEMU
+        uses: docker/setup-qemu-action@v3
+
       - name: Build and push Docker image
         uses: docker/build-push-action@v6
         with: