Fix codecov to ignore 3rdparty folder

[henrygerardmoore]

It looks like we're trying to ignore codecov for the 3rd party folder, but it's included nonetheless. This PR fixes that to get a more accurate codecov value

Currently:

After this PR: [trying to get codecov to cooperate]

[facontidavide]

Looks good to me, this is something I was struggling with! Let me know when it is ready for review

[henrygerardmoore]

Looks good to me, this is something I was struggling with! Let me know when it is ready for review

I tried a million different things and couldn't get it :melting_face: ! I will let you know when it's ready though :+1:

[henrygerardmoore]

Giving up on this for now, I'll try it again at some point.