Add Docker layer caching

.github/workflows/update-base-image.yml

@@ -11,6 +11,14 @@ jobs:
       -
         name: Set up Docker Buildx
         uses: docker/setup-buildx-action@v1
+      -
+        name: Cache Docker layers
+        uses: actions/cache@v2
+        with:
+          path: /tmp/.buildx-cache
+          key: ${{ runner.os }}-buildx-${{ github.sha }}
+          restore-keys: |
+            ${{ runner.os }}-buildx-
       -
         name: Login to GitHub Container Registry
         uses: docker/login-action@v1 
@@ -41,6 +49,16 @@ jobs:
             ghcr.io/sethsimmons/simple-monerod-docker/simple-monerod:${{ steps.get_tag.outputs.tag }}
             sethsimmons/simple-monerod:latest
             sethsimmons/simple-monerod:${{ steps.get_tag.outputs.tag }}
+          cache-from: type=local,src=/tmp/.buildx-cache
+          cache-to: type=local,dest=/tmp/.buildx-cache-new
+      -
+        # Temp fix
+        # https://github.com/docker/build-push-action/issues/252
+        # https://github.com/moby/buildkit/issues/1896
+        name: Move cache
+        run: |
+          rm -rf /tmp/.buildx-cache
+          mv /tmp/.buildx-cache-new /tmp/.buildx-cache
       -
         name: Image digest
         run: echo ${{ steps.docker_build.outputs.digest }}