added steamcmd images and update buildx to latest

steamcmd/dotnet/Dockerfile

@@ -0,0 +1,34 @@
+FROM    --platform=$BUILDPLATFORM debian:bullseye-slim
+
+LABEL   author="Torsten Widmann" maintainer="info@goover.de"
+
+ENV     DEBIAN_FRONTEND noninteractive
+
+RUN     dpkg --add-architecture i386 \
+          && apt update \
+          && apt upgrade -y \
+          && apt install -y tar curl gcc g++ lib32gcc-s1 libgcc1 libcurl4-gnutls-dev:i386 libssl1.1:i386 libcurl4:i386 lib32tinfo6 libtinfo6:i386 lib32z1 lib32stdc++6 libncurses5:i386 libcurl3-gnutls:i386 libsdl2-2.0-0:i386 iproute2 gdb libsdl1.2debian libfontconfig1 telnet net-tools netcat tzdata \
+          && apt install -y libstdc++6 libstdc++6:i386 libc6-amd64 libc6:i386 psmisc libgdiplus libcurl4 libfontconfig1 libpangocairo-1.0-0 libnss3 libgconf-2-4 libxi6 libxcursor1 libxss1 libxcomposite1 libasound2 libxdamage1 libxtst6 libatk1.0-0 libxrandr2 libcurl4 xvfb mesa-utils git \
+          && apt install -y python3 python3-dev python3-pip apt-transport-https wget iproute2 sqlite3 \
+          && useradd -d /home/container -m container
+
+RUN     apt update -y \
+          && apt upgrade -y \
+          && wget https://packages.microsoft.com/config/debian/11/packages-microsoft-prod.deb -O packages-microsoft-prod.deb \
+          && dpkg -i packages-microsoft-prod.deb \
+          && rm packages-microsoft-prod.deb \
+          && apt update -y \
+          && apt install -y aspnetcore-runtime-7.0 dotnet-sdk-7.0 libgdiplus
+
+## install rcon
+RUN     cd /tmp/ \
+          && curl -sSL https://github.com/gorcon/rcon-cli/releases/download/v0.10.2/rcon-0.10.2-amd64_linux.tar.gz > rcon.tar.gz \
+          && tar xvf rcon.tar.gz \
+          && mv rcon-0.10.2-amd64_linux/rcon /usr/local/bin/
+
+USER    container
+ENV     USER=container HOME=/home/container
+WORKDIR /home/container
+
+COPY    ./../entrypoint.sh /entrypoint.sh
+CMD     ["/bin/bash", "/entrypoint.sh"]