Probably worth adding tarpaulin + coveralls

[k3yavi]

Hi @jperkel ,

The repo look great ! I I just have a minor suggestion to improve & maintain the robustness of the code. Through github actions and tarpaulin you can also track what percentage of your source code is covered through unit tests, coveralls also provides a nice web interface to track it. Just as an example check this out for one of my repo, the code to add can be found here.