update folderstructure to match xdg-ninja

zsh/.local/share/oh-my-zsh/.oh-my-zsh/plugins/heroku/README.md

@@ -0,0 +1,9 @@
+# Heroku
+
+This plugin provides completion for the [Heroku CLI](https://devcenter.heroku.com/articles/heroku-cli).
+
+To use it add heroku to the plugins array in your zshrc file:
+
+```bash
+plugins=(... heroku)
+```

zsh/.local/share/oh-my-zsh/.oh-my-zsh/plugins/heroku/heroku.plugin.zsh

@@ -0,0 +1,9 @@
+if [[ "$OSTYPE" = darwin* ]]; then
+  cache_dir="${HOME}/Library/Caches"
+else
+  cache_dir="${XDG_CACHE_HOME:-"${HOME}/.cache"}"
+fi
+
+setup_path="${cache_dir}/heroku/autocomplete/zsh_setup"
+[[ -f "$setup_path" ]] && source $setup_path
+unset cache_dir setup_path