Update git submodules

* Update docs/submodules/sdnc/oam.git from branch 'master'
  to 6a42d5eee5d71870527c8a302308f3e49829a496
  - Topology Discovery and optical-service DGs
    to support MDONS usecase
    
    Change-Id: I1c28e799cc83325e8913d17ee8b718b0a4160cb2
    Issue-ID: SDNC-928
    Signed-off-by: Franklin Dsilva <franklin.dsilva@us.fujitsu.com>
    
diff --git a/docs/submodules/sdnc/oam.git b/docs/submodules/sdnc/oam.git
index b5cd53a..6a42d5e 160000
--- a/docs/submodules/sdnc/oam.git
+++ b/docs/submodules/sdnc/oam.git
@@ -1 +1 @@
-Subproject commit b5cd53a8da9d5a4707875e97d6975097217e9545
+Subproject commit 6a42d5eee5d71870527c8a302308f3e49829a496