commit c0d644d00ab849f4506f17a98a5740bf0feff020
author Jay Conrod <jayconrod@google.com> Mon Mar 16 17:44:38 2020 -0400
committer Jay Conrod <jayconrod@google.com> Mon Aug 24 16:22:28 2020 +0000
tree 2135afe0a833d60d8d35191bb5c4e21aa8268d6e
parent 89ce4c7ba8043b0e8a8c03f1a266fb0e56637314

modfile: support retract directive and version intervals

This CL adds support for parsing and programmatically adding and
removing a new directive, "retract", as described in golang/go#24031.

The "retract" directive comes in two forms:

    retract v1.0.0           // single version
    retract [v1.1.0, v1.2.0] // closed interval

Updates golang/go#24031

Change-Id: I1236c7d89e7674abf694e49e9b4869b14a59fac0
Reviewed-on: https://go-review.googlesource.com/c/mod/+/228039
Run-TryBot: Jay Conrod <jayconrod@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Michael Matloob <matloob@golang.org>