(devel/R-pkgcache) Updated 2.0.4 to 2.1.1

# pkgcache 2.1.1

* `parse_installed()` now has a `packages` argument, to list only a subset
  of all packages.

* `parse_packages()` can now parse `PACKAGES` files with trailing
  whitespace (#93).

* The Bioconductor repositories now include the 'books' repository,
  available since Bioconductor 3.12.

# pkgcache 2.1.0

* pkgcache now supports binary packages on x86_64 macOS and R 4.3.0 and
  later (#89).

* Better Posit Package Manager (PPM) support. New `ppm_has_binaries()`,
  `ppm_r_versions()`, `ppm_repo_url()`, `ppm_snapshots()` and `ppm_platforms()`
  functions to help interacting with PPM. See the new 'pkgcache and Posit
  Package Manager on Linux' article at https://r-lib.github.io/pkgcache.
  (#47 and r-lib/pkgdepends#186).

(mef)