feat: add arm v7 as docker multi arch target (#679)

Author: mcntrn

.github/workflows/build-container.yaml

@@ -62,7 +62,7 @@ jobs:
         uses: docker/build-push-action@v2
         with:
           context: .
-          platforms: linux/amd64,linux/arm64
+          platforms: linux/amd64,linux/arm64,linux/arm/v7
           push: ${{ env.GHCR_USERNAME != '' }}
           tags: ${{ steps.docker_meta.outputs.tags }}
           labels: ${{ steps.docker_meta.outputs.labels }}