+getTags, getTagsByName method

[Gunzik]

Added api method

[woojos]

Hi Gunzik

Tag by name can be implemented in different way. API allows filtering by adding query param like it is descripbe in docs https://apidocs.getresponse.com/v3/resources/tags#tags.get.all. I would suggest method getTagByName has body return $this->call('tags?query[name]='.$tagName);