Combine runs

Dockerfile

@@ -67,18 +67,17 @@ ENV POSTGREY_TEXT="Delayed by postgrey"
 
 # --- prep
 SHELL ["/bin/bash", "-Eeuo", "pipefail", "-c"]
+# --- set timezone and locale
+ENV LANG "${BUILD_LOCALE}.UTF-8"
+ENV LANGUAGE "${BUILD_LOCALE}:en"
+ENV LC_ALL "${BUILD_LOCALE}.UTF-8"
 # hadolint ignore=SC1091
 RUN . /etc/os-release && \
     touch /etc/apt/sources.list && \
     echo "deb-src http://deb.debian.org/debian $VERSION_CODENAME main non-free-firmware" >> /etc/apt/sources.list && \
     echo "deb-src http://deb.debian.org/debian $VERSION_CODENAME-updates main non-free-firmware" >> /etc/apt/sources.list && \
-    echo "deb-src http://deb.debian.org/debian-security/ $VERSION_CODENAME-security main non-free-firmware" >> /etc/apt/sources.list
-
-# --- set timezone and locale
-ENV LANG "${BUILD_LOCALE}.UTF-8"
-ENV LANGUAGE "${BUILD_LOCALE}:en"
-ENV LC_ALL "${BUILD_LOCALE}.UTF-8"
-RUN apt-get -qq -o Dpkg::Use-Pty=0 update && \
+    echo "deb-src http://deb.debian.org/debian-security/ $VERSION_CODENAME-security main non-free-firmware" >> /etc/apt/sources.list && \
+    apt-get -qq -o Dpkg::Use-Pty=0 update && \
     apt-get -qq -o Dpkg::Use-Pty=0 --no-install-recommends install apt-utils locales && \
     sed -i -e "s/# ${BUILD_LOCALE}.UTF-8 UTF-8/${BUILD_LOCALE}.UTF-8 UTF-8/" /etc/locale.gen && \
     locale-gen && \