update buildx to v0.13.0

Signed-off-by: Tonis Tiigi <tonistiigi@gmail.com>

common.mk

@@ -39,7 +39,7 @@ REF                ?= HEAD
 DOCKER_CLI_REF     ?= $(REF)
 DOCKER_ENGINE_REF  ?= $(REF)
 DOCKER_COMPOSE_REF ?= v2.24.6
-DOCKER_BUILDX_REF  ?= v0.12.1
+DOCKER_BUILDX_REF  ?= v0.13.0
 
 # Use "stage" to install dependencies from download-stage.docker.com during the
 # verify step. Leave empty or use any other value to install from download.docker.com