fix: add missing build type behavior

- Add argument to container file.

Signed-off-by: Gabriel Nützi <gnuetzi@gmail.com>

Containerfile

@@ -20,6 +20,10 @@ ADD /root/ /root/
 ADD /etc/ /etc/
 ADD /home/ /home/
 
+# The build type: either `dev` or `prod`
+# In `dev` mode: the package manager will not be deleted.
+ARG BUILD_TYPE=prod
+
 # Allow image-builders to choose another version besides "latest" should
 # an incompatible change be introduced.
 ARG RUNNER_VERSION=latest
@@ -35,9 +39,11 @@ ARG TARGETARCH=amd64
 ARG PRUNE_INTERVAL=daily  # see systemd.timer for allowable values
 
 # All-in-one packaging/image-setup script to keep things simple.
-RUN PRUNE_INTERVAL=${PRUNE_INTERVAL} \
-    RUNNER_VERSION=${RUNNER_VERSION} \
-    bash /root/setup.sh
+RUN \
+ PRUNE_INTERVAL=${PRUNE_INTERVAL} \
+ RUNNER_VERSION=${RUNNER_VERSION} \
+ BUILD_TYPE=${BUILD_TYPE} \
+ bash /root/setup.sh
 
 VOLUME /cache /home/podman/.local/share/containers
 ENTRYPOINT /lib/systemd/systemd