GOVERNANCE: List selinux project

Catching up with opencontainers/tob@0057edc (Merge pull request opencontainers#29
from opencontainers/selinux-project, 2017-02-23) and the subsequent
rename [1].

I'd still rather drop the parenthetical entirely and link to a place
that listed OCI Projects, but we don't have a canonical target for
that yet (opencontainers/tob#2) and the current closest instance seems
to be the GitHub section in [2] (which doesn't have the "OCI Project"
words).

[1]: opencontainers/selinux#6 (comment)
[2]: https://www.opencontainers.org/community

Signed-off-by: W. Trevor King <wking@tremily.us>

GOVERNANCE.md

@@ -34,7 +34,7 @@ For projects that are not specifications, a [motion to release](#release-approva
 ## Amendments
 
 The [project governance](#project-governance) rules and procedures MAY be amended or replaced using the procedures themselves.
-The MAINTAINERS of this project governance document is the total set of MAINTAINERS from all Open Containers projects (go-digest, image-spec, image-tools, runC, runtime-spec, and runtime-tools).
+The MAINTAINERS of this project governance document is the total set of MAINTAINERS from all Open Containers projects (go-digest, image-spec, image-tools, runC, runtime-spec, runtime-tools, and selinux).
 
 ## Subject templates