This will enable the new "git-codereview merge" command, and improve
targeting of "git-codereview mail".
Change-Id: I176c86f1e6cee9be3288565342673cf58079a72d
Reviewed-on: https://go-review.googlesource.com/c/go/+/290169
Trust: Filippo Valsorda <filippo@golang.org>
Run-TryBot: Filippo Valsorda <filippo@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>