.NET 5 SDK Docker container with more runtimes

dotnet.Dockerfile

FROM mcr.microsoft.com/dotnet/sdk:5.0

# Install Mono slim verion
# https://github.com/mono/docker
ENV MONO_VERSION 6.12.0.107

RUN apt-get update \
  && apt-get install -y --no-install-recommends gnupg dirmngr \
  && rm -rf /var/lib/apt/lists/* \
  && export GNUPGHOME="$(mktemp -d)" \
  && gpg --batch --keyserver hkp://keyserver.ubuntu.com:80 --recv-keys 3FA7E0328081BFF6A14DA29AA6A19B38D3D831EF \
  && gpg --batch --export --armor 3FA7E0328081BFF6A14DA29AA6A19B38D3D831EF > /etc/apt/trusted.gpg.d/mono.gpg.asc \
  && gpgconf --kill all \
  && rm -rf "$GNUPGHOME" \
  && apt-key list | grep Xamarin \
  && apt-get purge -y --auto-remove gnupg dirmngr

RUN echo "deb http://download.mono-project.com/repo/debian stable-buster/snapshots/$MONO_VERSION main" > /etc/apt/sources.list.d/mono-official-stable.list \
  && apt-get update \
  && apt-get install -y mono-runtime \
  && rm -rf /var/lib/apt/lists/* /tmp/*


# Instructions to install .NET Core runtimes from
# https://docs.microsoft.com/en-us/dotnet/core/install/linux-package-manager-debian10
RUN wget https://packages.microsoft.com/config/debian/10/packages-microsoft-prod.deb -O packages-microsoft-prod.deb && \
    dpkg -i packages-microsoft-prod.deb && \
    apt-get update && apt-get install -y \
        apt-transport-https \
        aspnetcore-runtime-2.1 \
        aspnetcore-runtime-3.0 \
        aspnetcore-runtime-3.1