Dockerfile: Update buildx to 0.30.1

Signed-off-by: Lincoln Wallace <lincoln.wallace@canonical.com>

Author: locnnil

Dockerfile

@@ -21,7 +21,7 @@ ARG DOCKERCLI_INTEGRATION_REPOSITORY="https://github.com/docker/cli.git"
 ARG DOCKERCLI_INTEGRATION_VERSION=v25.0.5
 
 # BUILDX_VERSION is the version of buildx to install in the dev container.
-ARG BUILDX_VERSION=0.29.1
+ARG BUILDX_VERSION=0.30.1
 
 # COMPOSE_VERSION is the version of compose to install in the dev container.
 ARG COMPOSE_VERSION=v2.40.0