Update swarm v1.2.8

Signed-off-by: Nishant Totla <[email protected]>

library/swarm

@@ -5,8 +5,5 @@ Maintainers: Alexandre Beslic <[email protected]> (@abronan),
              Victor Vieux <[email protected]> (@vieux)
 GitRepo: https://github.com/docker/swarm-library-image.git
 
-Tags: 1.2.8-rc1
-GitCommit: b28650fbd0f447b821505d2ec18667fbbde8a108
-
-Tags: 1.2.7, latest
-GitCommit: b741365fdf375bb7409314b4a161a91290935d3f
+Tags: 1.2.8, latest
+GitCommit: 741c78fb0287dc0850f5f131e099610a7acc2bf9