Add HOST_BASE_VERSION.

 ARG DOCKER_VERSION=26.1.3
 ARG DOCKER_BUILDX_VERSION=0.20.1
+ARG HOST_BASE_VERSION=bookworm-20241223-slim
 ARG HELM_VERSION=3.16.4
 ARG HELM_DIFF_VERSION=3.5.0
 ARG HELM_GIT_VERSION=1.3.0
@@ -47,8 +48,7 @@ FROM scratch AS skopeo-remote
 ARG SKOPEO_VERSION
 ADD https://github.com/containers/skopeo/archive/refs/tags/v${SKOPEO_VERSION}.tar.gz /srv/skopeo.tar.gz
 
-FROM debian:bookworm-20241223-slim AS host-base-tools
-
+FROM debian:${HOST_BASE_VERSION} AS host-base-tools
 RUN	true && \
 	apt-get update && \
 	apt-get install -y bash-completion git libgpgme11 libsubid4 libdevmapper1.02.1 && \