Add gh package into R-Instat

[lilyclements]

This is a small package which is just used to access bits from Github within R-Instat. On @Vitalis95's PR #8858 we use the gh package.

Can the gh package be added into R-Instat?

@Fidel365 I think you added the package in last time - do you know how to do this? THanks!

[Fidel365]

@lilyclements , I can see the gh package is already installed in R-instat?

[lilyclements]

@Fidel365 good point - you're right! I should have most definitely checked this before setting up the issue... My bad. Thanks for checking