master workflow, builds amd64-only :latest and :latest-debug

- arm64 via qemu is waaay too slow
- tags are still multiarch

.github/workflows/master-latest.yaml

@@ -12,14 +12,7 @@ jobs:
       - name: Checkout
         uses: actions/checkout@v2
 
-      # Setup qEMU for arm64
+      # We use buildx instead of regular build so we can take advantage of Docker layer cache via GithubActions' cache
-      - name: Set up QEMU
-        uses: docker/setup-qemu-action@v1
-        with:
-          platforms: arm64
-
-      # We use buildx instead of regular build so we can take advantage of Docker layer cache via GithubActions's cache
-      # Also buildx offers multi-arch builds
       - name: Set up Docker Buildx
         id: buildx
         uses: docker/setup-buildx-action@v1
@@ -54,7 +47,7 @@ jobs:
           tags: rpardini/docker-registry-proxy:latest
           push: true
           cache-from: type=local,src=/tmp/.buildx-cache/release
-          # first run does not export the cache
+          cache-to: type=local,mode=max,dest=/tmp/.buildx-cache/release
 
       - name: Build and push amd64 Debug Docker Image to DockerHub
         uses: docker/build-push-action@v2
@@ -67,33 +60,4 @@ jobs:
           tags: rpardini/docker-registry-proxy:latest-debug
           push: true
           cache-from: type=local,src=/tmp/.buildx-cache/debug
-          # first run does not export the cache
-
-      # Do it all again with both archs. the amd64 will be a huge cache hit
-      # this will update the manifest have both arches
-      - name: Build and push multiarch Release Docker Image to DockerHub
-        uses: docker/build-push-action@v2
-        with:
-          build-args: DEBUG_BUILD=0,BASE_IMAGE_SUFFIX=
-          builder: ${{ steps.buildx.outputs.name }}
-          context: .
-          file: ./Dockerfile
-          platforms: linux/arm64,linux/amd64
-          tags: rpardini/docker-registry-proxy:latest
-          push: true
-          cache-from: type=local,src=/tmp/.buildx-cache/release
-          cache-to: type=local,mode=max,dest=/tmp/.buildx-cache/release
-
-      - name: Build and push multiarch Debug Docker Image to DockerHub
-        uses: docker/build-push-action@v2
-        with:
-          build-args: DEBUG_BUILD=1,BASE_IMAGE_SUFFIX=-debug
-          builder: ${{ steps.buildx.outputs.name }}
-          context: .
-          file: ./Dockerfile
-          platforms: linux/arm64,linux/amd64
-          tags: rpardini/docker-registry-proxy:latest-debug
-          push: true
-          cache-from: type=local,src=/tmp/.buildx-cache/debug
           cache-to: type=local,mode=max,dest=/tmp/.buildx-cache/debug
-