Exit script/setup if node is not found

This mirrors what the script already does if ruby is not found

script/setup

@@ -29,6 +29,7 @@ fi
 # Check node version
 if ! node --version | grep $NODE_VERSION > /dev/null; then
   printf "${RED}Open Food Network requires node ${NODE_VERSION}${NO_COLOR}. Have a look at: https://github.com/nodenv/nodenv\n"
+  exit 1
 fi
 
 # Set up Ruby dependencies via Bundler