build: Update qemu-docker to v6.18 (#1065)

Dockerfile

@@ -1,7 +1,7 @@
 ARG VERSION_ARG="latest"
 FROM scratch AS build-amd64
 
-COPY --from=qemux/qemu-docker:6.17 / /
+COPY --from=qemux/qemu:6.18 / /
 
 ARG DEBCONF_NOWARNINGS="yes"
 ARG DEBIAN_FRONTEND="noninteractive"