Upgrade GH actions to use more base R

[jangorecki]

Another great work by @yihui https://github.com/yihui/actions

[yihui]

Oh you've already discovered it! I just created these actions this week. I've wished to do it for a few years and finally did it with the help of Copilot. r-lib's setup-r-depencencies uses {pak}, which has zero dependencies in theory, but only in theory; its check-r-package uses {rcmdcheck}, which depends on callr cli curl desc digest pkgbuild prettyunits R6 rprojroot sessioninfo withr xopen processx ps while I'm perfectly happy with the good old R CMD check. My own packages often have a very small number of dependencies, so I feel {pak} is an overkill for me and I'd rather parsing DESCRIPTION directly and install.packages().

That said, my actions are only 3 days old and definitely not tested thoroughly. I'd welcome and appreciate any feedback!