adds buildx as a builder

Author: petethepig

.github/workflows/docker-dev-images.yml

@@ -1,4 +1,4 @@
-name: Push docker dev image to Dockerhub
+name: Push Docker Dev Image to Dockerhub
 
 on:
   push:
@@ -38,6 +38,7 @@ jobs:
         id: docker_build
         uses: docker/build-push-action@v2
         with:
+          builder: ${{ steps.buildx.outputs.name }}
           context: ./
           file: ./Dockerfile
           push: true