Removed dependencies on fs, dplyr, readr in tests to pass CRAN package checks.
Fixed bug in file_cache() when suggested packages were not available.
Made explicit the dependency R (>= 4.1.0) due to use of new pipe |> in tests and examples.
test-cached_read to pass CRAN Package Check. Copied test data to a temporary directory to perform tests there.test-cached_read to pass CRAN Package Check.file_cache(cache=NULL) (default) now uses a sub-folder “cache” rather than the top directory.