print version # and exit option

[chrisgulvik]

This is related to Issue #14. You're using getopts bash which doesn't support long --version opts, so understandably you couldn't easily change that. Would it be possible to add to the scrub.sh a -v option to print out the software version number and exit without requiring a file to process?

Even a "sra-human-scrubber v2.2.1" in the scrub.sh help menu would be useful if the extra -v opt is too much tinkering. My hope is just to grab the version number without wasting CPU resources on a testfile.

Your CHANGELOG.md lists the latest version, but that's not available for conda and docker.