devel/myrepos: Re-add port and update to 1.20180726

Changelog: https://git.joeyh.name/index.cgi/myrepos.git/log/?h=1.20180726

PR: 251921
Submitted by: Chris Hutchinson <portmaster@bsdforge.com> (new maintainer)
Approved by: arrowd (mentor)
Differential Revision: https://reviews.freebsd.org/D27810