Fix missing python3 runtime

Author: hbruch

Dockerfile

@@ -18,6 +18,7 @@ RUN apt-get update && apt-get install -y \
     ca-certificates \
     gnupg \
     lsb-release \
+    python3 \
   && curl -fsSL https://download.docker.com/linux/ubuntu/gpg | gpg --dearmor -o /usr/share/keyrings/docker-archive-keyring.gpg \
   && echo \
     "deb [arch=$(dpkg --print-architecture) signed-by=/usr/share/keyrings/docker-archive-keyring.gpg] https://download.docker.com/linux/ubuntu \