Invite RapidCheck to the challenge

[Nicolas DUBIEN]

The library RapidCheck from @emil-e is the property based testing library I used for a while when doing C++. I believe it could be cool to propose him to join too.

More generally, is it ok if I open issue linking to the challenge on some pbt libs or do you prefer to do it on your side?

[Johannes Link]

Go ahead. The more interest the better.

[Nicolas DUBIEN]

Thanks, I'll

[Nicolas DUBIEN]

Issue opened: emil-e/rapidcheck#270