Sign files & verify signatures. Works with signify in OpenBSD

Current version

minisign requires the following formulae to be installed:
libsodium 1.0.16 NaCl networking and cryptography library
cmake 3.11.1 Cross-platform make

Recent formula history

ilovezfs minisign 0.8
ilovezfs Audit fixes for descriptions (#20013)
ilovezfs Use “squiggly” heredocs.
ilovezfs minisign: use assert_predicate instead of File.exist?
Dominyk Tiller minisign: revision bump for libsodium

Formula code at GitHub