Use registry mirror with docker GitHub Action:

This should alleviate the DockerHub rate limiting
issues.

Signed-off-by: Jacob Weinstock <jakobweinstock@gmail.com>

Author: jacobweinstock

.github/workflows/build-all-matrix.yaml

@@ -78,6 +78,10 @@ jobs:
 
       - name: Set up Docker Buildx
         uses: docker/setup-buildx-action@v3
+        with:
+          buildkitd-config-inline: |
+            [registry."docker.io"]
+              mirrors = ["mirror.gcr.io"]
 
       - name: Docker Login to quay.io
         if: ${{ env.REGISTRY == 'quay.io' && github.ref == 'refs/heads/main' }}
@@ -119,6 +123,10 @@ jobs:
 
       - name: Set up Docker Buildx # nb: no need for qemu here, kernels are cross-compiled, instead of the compilation being emulated
         uses: docker/setup-buildx-action@v3
+        with:
+          buildkitd-config-inline: |
+            [registry."docker.io"]
+              mirrors = ["mirror.gcr.io"]
 
       - name: Docker Login to quay.io
         if: ${{ env.REGISTRY == 'quay.io' && github.ref == 'refs/heads/main' }}
@@ -159,6 +167,10 @@ jobs:
 
       - name: Set up Docker Buildx # nb: no need for qemu here, kernels are cross-compiled, instead of the compilation being emulated
         uses: docker/setup-buildx-action@v3
+        with:
+          buildkitd-config-inline: |
+            [registry."docker.io"]
+              mirrors = ["mirror.gcr.io"]
 
       - name: Docker Login to DockerHub # read-only token, required to be able to pull all the linuxkit pkgs without getting rate limited.
         if: ${{ env.LOGIN_TO_DOCKERHUB == 'yes' && github.ref == 'refs/heads/main' }}