Replace hardcoded arm64 by auto detected architecture

Signed-off-by: Bernd.Rederlechner@t-systems.com <bernd.rederlechner@t-systems.com>

.devcontainer/Dockerfile

@@ -61,7 +61,7 @@ RUN apt-get -y install \
     software-properties-common && \
     curl -fsSL https://download.docker.com/linux/ubuntu/gpg | apt-key add - && \
     add-apt-repository \
-   "deb [arch=amd64] https://download.docker.com/linux/ubuntu \
+   "deb [arch=$(dpkg --print-architecture)] https://download.docker.com/linux/ubuntu \
    $(lsb_release -cs) \
    stable" && \
     apt-get update -y && \