Update readme.md

[bn-l]

It has been frustrating getting typescript to work with AVA nicely. Googling information on this is a lost cause these days with the quality of the results. I have spent a lot of time and it is very frustrating to decipher just how to best set up AVA in general, today, 08/03/2024 using modern javascript (typescript).

I think this warning would also prevent new issues and discussions. It really should be the first thing people see when going to the github.