Do not require generating a new coverage report every time

[Mbuckley0]

I have a github repo which contains multiple projects inside the same repo with each project being in a different folder. Right now we have to run tests for every project/folder in the repo so that we can generate and upload the full coverage report. I want to only run tests for projects that were changed and either only upload the coverage for those folders or pull existing coverage files for the folders that did not changed and sum+upload the total report that way.