revert: docker matrix build

Apparently matrix builds don't work with the docker action.

Only reference I found about the topic: https://github.com/docker/build-push-action/issues/130

Signed-off-by: Mark Sagi-Kazar <mark.sagikazar@gmail.com>

.github/workflows/artifacts.yaml

@@ -14,10 +14,6 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        platform:
-          - linux/amd64
-          - linux/arm/v7
-          - linux/arm64
         variant:
           - alpine
           - distroless
@@ -62,7 +58,7 @@ jobs:
       - name: Set up QEMU
         uses: docker/setup-qemu-action@v1
         with:
-          platforms: arm64,arm
+          platforms: all
 
       - name: Set up Docker Buildx
         uses: docker/setup-buildx-action@v1
@@ -86,7 +82,7 @@ jobs:
         uses: docker/build-push-action@v2
         with:
           context: .
-          platforms: ${{ matrix.platform }}
+          platforms: linux/amd64,linux/arm/v7,linux/arm64
           cache-from: type=gha
           cache-to: type=gha,mode=max
           push: ${{ github.event_name == 'push' }}