update workflow

.github/workflows/buildx.yaml

@@ -20,7 +20,7 @@ jobs:
         fi
 
         echo ::set-output name=build_date::$(date -u +'%Y-%m-%dT%H:%M:%SZ')
-        echo ::set-output name=docker_platforms::linux/amd64,linux/arm/v6,linux/arm/v7,linux/arm64,linux/386,linux/ppc64le,linux/s390x
+        echo ::set-output name=docker_platforms::linux/amd64,linux/arm/v6,linux/arm/v7,linux/arm64,linux/386
         echo ::set-output name=docker_image::${{ secrets.DOCKER_USERNAME }}/${{ github.event.repository.name }}
 
       # https://github.com/crazy-max/ghaction-docker-buildx