Fixed RVM segment for usernames with dashes

Having a username with a dash, such as mine, `d-side`, currently results in RVM segment displaying the wrong thing, e. g. `side/.rvm/rubies/ruby`. This fixes the issue.

powerlevel9k.zsh-theme

@@ -990,7 +990,7 @@ prompt_rvm() {
   local gemset=$(echo $GEM_HOME | awk -F'@' '{print $2}')
   [ "$gemset" != "" ] && gemset="@$gemset"
 
-  local version=$(echo $MY_RUBY_HOME | awk -F'-' '{print $2}')
+  local version=$(echo $MY_RUBY_HOME | awk -F'-' '{print $NF}')
 
   if [[ -n "$version$gemset" ]]; then
     "$1_prompt_segment" "$0" "$2" "240" "$DEFAULT_COLOR" "$version$gemset" 'RUBY_ICON'