add git installation step into Dockerfile

Author: aerubanov

scripts/Dockerfile

@@ -5,6 +5,9 @@ LABEL description="Environment for PyMC version 4"
 
 ENV LANG=C.UTF-8 LC_ALL=C.UTF-8
 
+USER root
+RUN apt-get update && apt-get install -y git
+
 # Switch to jovyan to avoid container runs as root
 USER $NB_UID