* Updated to Github actions v4 as Github actions v3 will be closing down by 1/30/25.
* Updated to use actions/checkout action at the v4 branch as well to be consistent with artifacts. It is recommended to use a sepcific version or tag instead of master to ensure stability and predictability.
* Made the artifact name unique within the workflow run.
* Add code-coverage make target and github actions workflow
* Upload coverage to coveralls
* Add coverage badge to readme
* Fix some test makefiles to correctly propagate flags