fix docker install step

scripts/install.sh

@@ -243,7 +243,6 @@ EOF
         docker-ce \
         --no-install-recommends
 
-    groupadd docker
     addgroup ${USERNAME} docker
 
     docker version
@@ -254,7 +253,7 @@ install_compose() {
     # https://github.com/docker/compose/releases
     # btw: *not* for raspbian! you got 3 choices: hypriot, install via pip or build yourself
     # https://www.berthon.eu/2017/getting-docker-compose-on-raspberry-pi-arm-the-easy-way/
-    VERS="1.21.2"
+    VERS="1.23.2"
     FILE="docker-compose-$(uname -s)-$(uname -m)"
     echo "installing docker-compose $VERS ... curling from github"