Code Coverage should not be checking the third party libraries for coverage

[gioce90]

Following this comment here #20 (comment)

I think that when we run the Code coverage, this should only focus on the code of the solution we are testing and should not also include external dependencies like in this example:

Luckily with the advent of IncludeTestAssembly=false we have at least excluded test projects, as requested here. I think it's a good idea to extend this limit to third-party libraries as well.

[jakubch1]

Duplicate of #12