chore: switch buildkit image to mcr registry (#761)

**Reason for Change**:

switch buildkit image to mcr registry to avoid dockerhub
pull rate limit.

Signed-off-by: jerryzhuang <zhuangqhc@gmail.com>

Makefile

@@ -208,6 +208,7 @@ BUILDX_BUILDER_NAME ?= img-builder
 OUTPUT_TYPE ?= type=registry
 QEMU_VERSION ?= 7.2.0-1
 ARCH ?= amd64,arm64
+BUILDKIT_VERSION ?= v0.18.1
 
 RAGENGINE_IMAGE_NAME ?= ragengine
 RAGENGINE_IMAGE_TAG ?= v0.0.1
@@ -217,7 +218,7 @@ RAGENGINE_IMAGE_TAG ?= v0.0.1
 docker-buildx: ## Build and push docker image for the manager for cross-platform support
 	@if ! docker buildx ls | grep $(BUILDX_BUILDER_NAME); then \
 		docker run --rm --privileged mcr.microsoft.com/mirror/docker/multiarch/qemu-user-static:$(QEMU_VERSION) --reset -p yes; \
-		docker buildx create --name $(BUILDX_BUILDER_NAME) --use; \
+		docker buildx create --name $(BUILDX_BUILDER_NAME) --driver-opt image=mcr.microsoft.com/oss/v2/moby/buildkit:$(BUILDKIT_VERSION) --use; \
 		docker buildx inspect $(BUILDX_BUILDER_NAME) --bootstrap; \
 	fi