Module is released in drupal.org, get the updated recent code from https://www.drupal.org/project/starrating
Star Rating is a simple module that provides star rating field and display formatter using Drupal 8's Field Type API.
Unlike Fivestar module and other voting/rating module, it supports neither end user voting nor nice AJAX interface. It is inteded for the rating only by the author of the article (node). Of course, you may be able to do this with Fivestar module and other voting/rating modules, but unlike most of them, it does not require other modules such as voting API module. It's born to be simple but good enough for those who want star rating only by authors.
For example, if you are creating a restaurant review web site and you want to add three 5 star ratings (food, price and service) with different icon type for each rating within a node, then this module would be the best match.