Add gif to readme

[spboyer]

Add gif from MVP Conference presentation to readme.

[tonerdo]

@spboyer will definitely do that

[spboyer]

Let me know when you get this done, want to promote this...

[MarcoRossignoli]

Coverlet now it's a .NET foundation project and it's used by default by VS test for xpath coverage, @tonerdo did a great work now it's enough "promoted" 😄
I'll close this issue to cleanup a bit.