fix: dotnet installation

ubuntu_dev/Dockerfile.xenial

@@ -5,13 +5,11 @@ LABEL maintainer="Hive Solutions <[email protected]>"
 
 ARG DEBIAN_FRONTEND=noninteractive
 
-RUN echo "deb [arch=amd64] https://apt-mo.trafficmanager.net/repos/dotnet-release/ xenial main" > /etc/apt/sources.list.d/dotnetdev.list &&\
-    apt-key adv --keyserver apt-mo.trafficmanager.net --recv-keys 417A0893 &&\
-    apt-get update &&\
-    apt-get install -y -q --no-install-recommends sudo gcc make curl pypy dotnet-dev-1.0.0 linux-headers-generic\
+RUN apt-get update &&\
+    apt-get install -y -q --no-install-recommends apt-transport-https sudo gcc make curl pypy dotnet-dev-1.0.0 linux-headers-generic\
     libssl-dev python2-dev python3-dev pypy-dev &&\
-    apt-get clean && rm -rf /var/lib/apt/lists/* &&\
-    wget https://raw.githubusercontent.com/dotnet/core/master/release-notes/1.0/install-1.0.1.sh &&\
-    chmod +x install-1.0.1.sh && (echo "y" | bash install-1.0.1.sh) && rm install-1.0.1.sh
+    wget https://packages.microsoft.com/config/ubuntu/16.04/packages-microsoft-prod.deb -O /tmp/packages-microsoft-prod.deb &&\
+    dpkg -i /tmp/packages-microsoft-prod.deb && apt update && apt-get install dotnet-runtime-6.0 aspnetcore-runtime-6.0 &&\
+    rm -f /tmp/packages-microsoft-prod.deb && apt-get clean && rm -rf /var/lib/apt/lists/*
 
 CMD ["/bin/bash"]