Add node version, yarn version to pure prompt

partial-pure.zsh

# add before prompt_pure_preprompt_render
prompt_node_npm() {
  local nodeVersion=`node --version | sed -e "s/v//g"`
  local yarnVersion=`yarn --version`
  preprompt_parts+="%F{green}⬢%f $nodeVersion 📦 $yarnVersion"
}

## add below 
## Git pull/push arrows.
#  if [[ -n $prompt_pure_git_arrows ]]; then
#    preprompt_parts+=('%F{$prompt_pure_colors[git:arrow]}${prompt_pure_git_arrows}%f')
#  fi

# Add node and npm versions.
  prompt_node_npm