fix: Add post build script to prepare image for ISO creation

scripts/post_build.sh

@@ -0,0 +1,11 @@
+#!/usr/bin/env bash
+
+set -euo pipefail
+
+if ! command -v bootc; then
+  rpm-ostree install bootc
+fi
+
+bootupctl backend generate-update-metadata
+rm -fr /tmp/* /var/*
+ostree container commit

template/templates/Containerfile.j2

@@ -38,7 +38,8 @@ RUN --mount=type=bind,from=stage-bins,src=/bins,dst=/tmp/bins \
 
 {% call modules::main_modules_run(recipe.modules_ext, os_version) %}
 
-RUN rm -fr /tmp/* /var/* && ostree container commit
+RUN --mount=type=bind,from=ghcr.io/blue-build/cli:{{ exports_tag }}-build-scripts,src=/scripts/,dst=/scripts/ \
+  /scripts/post_build.sh
 
 # Labels are added last since they cause cache misses with buildah
 LABEL {{ blue_build_utils::constants::BUILD_ID_LABEL }}="{{ build_id }}"