Dockerfile: update buildx to v0.18.0

Update the buildx cli plugin used in the dev-container

full diff: https://github.com/docker/buildx/compare/0.17.1..0.18.0

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>

Dockerfile

@@ -8,7 +8,7 @@ ARG GO_VERSION=1.23.3
 ARG XX_VERSION=1.5.0
 ARG GOVERSIONINFO_VERSION=v1.3.0
 ARG GOTESTSUM_VERSION=v1.10.0
-ARG BUILDX_VERSION=0.17.1
+ARG BUILDX_VERSION=0.18.0
 ARG COMPOSE_VERSION=v2.29.7
 
 FROM --platform=$BUILDPLATFORM tonistiigi/xx:${XX_VERSION} AS xx