golang_renamer update for golang1.16 

It looks like an update for the project that `golang_renamer.py` is built on has an update for golang1.16

https://github.com/sibears/IDAGolangHelper/blob/master/GO_Utils/Gopclntab.py

Would it be possible to patch in the newer `check_is_gopclntab16`, `rename16` functions and `lookup16` data?

