git: openjdk/skara: Support the "neutral" check conclusion

[duke]

Changeset: 17f2684d
Author:    Robin Westberg <rwestberg at openjdk.org>
Committer: Robin Westberg <robin at westberg.se>
Date:      2019-11-05 10:37:13 +0000
URL:       https://git.openjdk.java.net/skara/commit/17f2684d

Support the "neutral" check conclusion

Reviewed-by: ehelin

! forge/src/main/java/org/openjdk/skara/forge/github/GitHubPullRequest.java