Fix docker build

.github/workflows/build-docker.yml

@@ -19,15 +19,26 @@ jobs:
   build:
     runs-on: ubuntu-latest
 
+    strategy:
+      matrix:
+        platform:
+          - linux/amd64
+          - linux/arm64
     steps:
-      - name: Check Out Repo
+      - name: Prepare
+        run: |
+          if [ "${{ matrix.platform }}" = "linux/amd64" ]; then
+            echo "TARGET_ARCH=x86_64" >> $GITHUB_ENV
+          elif [ "${{ matrix.platform }}" = "linux/arm64" ]; then
+            echo "TARGET_ARCH=aarch64" >> $GITHUB_ENV
+          fi
+      - name: Checkout
         uses: actions/checkout@v4
 
       - name: Set up QEMU
         uses: docker/setup-qemu-action@v3
 
       - name: Set up Docker Buildx
-        id: buildx
         uses: docker/setup-buildx-action@v3
 
       - name: Build
@@ -36,12 +47,8 @@ jobs:
         with:
           context: ./
           file: ./Dockerfile
-          platforms: linux/amd64,linux/arm64
-          builder: ${{ steps.buildx.outputs.name }}
           push: false
-          tags: ghci.io/${{ github.repository }}-manylinux_2_28_${{ runner.arch }}:latest
+          platforms: ${{ matrix.platform }}
+          tags: ghci.io/${{ github.repository }}-manylinux_2_28_$TARGET_ARCH:latest
           build-args: |
-            TARGET_ARCH=${{ runner.arch }}
-
-      - name: Image digest
-        run: echo ${{ steps.docker_build.outputs.digest }}
+            TARGET_ARCH=$TARGET_ARCH