minitar-cli 0.6

<tt>minitar-cli</tt> is a pure-Ruby command-line tool that uses {minitar}[https://github.com/halostatue/minitar] to provide a command-line tool, +minitar+, for working with POSIX tar(1) archive files. This is release 0.6, extracted from {minitar}[https://halostatue.ca/minitar], with modernizations.