more hadolint fixes

.hadolint.yaml

@@ -0,0 +1,2 @@
+ignored:
+  - DL3008

Dockerfile

@@ -3,12 +3,12 @@ LABEL maintainer "David J. M. Karlsen <[email protected]>"
 ARG OVERMIND_VERSION=v2.0.3
 ENV OVERMIND_SOCKET=/tmp/.overmind.sock
 SHELL ["/bin/bash", "-o", "pipefail", "-c"]
-RUN apt update && \
-    apt -y install daemontools git gosu tmux && \
-    apt clean && \
+RUN apt-get update && \
+    apt-get -y --no-install-recommends install daemontools git gosu tmux && \
+    apt-get clean && \
     curl --silent -L https://github.com/DarthSim/overmind/releases/download/${OVERMIND_VERSION}/overmind-${OVERMIND_VERSION}-linux-amd64.gz | zcat > /usr/local/bin/overmind && \
     chmod a+x /usr/local/bin/overmind && \
     useradd -c "application user" -d /app -s /bin/bash -m app -u 99 --system && \
-    find /var/cache/ -type f -delete
+    rm -rf /var/cache/apt /var/lib/apt/lists/* /tmp/* /var/tmp/*
 COPY entrypoint.sh /
 ENTRYPOINT ["/bin/bash", "/entrypoint.sh"]