https://github.com/djunsheep/CRANextra/blob/main/README.md

add the following to the .Rprifile and Rprofile.site

# fixing the CRANextra warnings when installing packages
# the following two chucks of scripts will/may run from start of R
local({
  r <- getOption("repos")  # Get the current repositories
  r <- r[names(r) != "CRANextra"]  # Remove CRANextra
  options(repos = r)  # Update the repositories
})

# the cloudyr project
# https://cloudyr.github.io/drat/
if (!require("drat")) {
    install.packages("drat")
    library("drat")
    drat::addRepo("cloudyr", "http://cloudyr.github.io/drat") # Add coudyr to repositories
}