This function used to check if a permanent cache was available and issue a
warning if not, but since {R.cache} version 0.15.0 (release date
2021-04-27), a permanent directory will be used automatically, so this check
if redundant. the function is kept in the package for compatibility, i.e.
if someone updates the R package {precommit} but not the hook revisions.
may_require_permanent_cache(temp_cache_is_enough = FALSE)ignored.
Other hook script helpers:
diff_requires_run_roxygenize(),
dirs_R.cache(),
precommit_docopt(),
robust_purl(),
roxygen_assert_additional_dependencies(),
roxygenize_with_cache()