Add source container, update GitHub Actions workflow

source/Dockerfile

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+#
+# Copyright (c) 2020 Matthew Penner
+#
+# This repository is licensed under the MIT License.
+# https://github.com/matthewpi/images/blob/master/LICENSE.md
+#
+
+FROM        debian:stable-slim
+
+LABEL       author="Matthew Penner" maintainer="matthew@pterodactyl.io"
+
+ENV         DEBIAN_FRONTEND=noninteractive
+
+RUN         dpkg --add-architecture i386 \
+				&& apt update \
+				&& apt upgrade -y \
+				&& apt install -y tar curl gcc g++ lib32gcc1 libgcc1 libcurl4-gnutls-dev:i386 libssl1.0.0:i386 libcurl4:i386 lib32tinfo5 libtinfo5:i386 lib32z1 lib32stdc++6 libncurses5:i386 libcurl3-gnutls:i386 iproute2 gdb libsdl1.2debian libfontconfig telnet net-tools netcat tzdata \
+				&& useradd -m -d /home/container container
+
+USER        container
+ENV         USER=container HOME=/home/container
+WORKDIR     /home/container
+
+COPY        ./entrypoint.sh /entrypoint.sh
+CMD         [ "/bin/bash", "/entrypoint.sh" ]

source/entrypoint.sh

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+#!/bin/ash
+
+#
+# Copyright (c) 2020 Matthew Penner
+#
+# This repository is licensed under the MIT License.
+# https://github.com/matthewpi/images/blob/master/LICENSE.md
+#
+
+# Default the TZ environment variable to UTC.
+TZ=${TZ:-UTC}
+export TZ
+
+# Switch to the container's working directory
+cd /home/container
+
+# Set environment variable that holds the Internal Docker IP
+export INTERNAL_IP=`ip route get 1 | awk '{print $NF;exit}'`
+
+# Replace variables in the startup command
+MODIFIED_STARTUP=`eval echo $(echo ${STARTUP} | sed -e 's/{{/${/g' -e 's/}}/}/g')`
+echo "[container@pterodactyl ~]$ ${MODIFIED_STARTUP}"
+
+# Run the startup command
+eval ${MODIFIED_STARTUP}