Update git submodules

* Update docs/submodules/snaps from branch 'master'
  - Merge "Added validation router is attached to the external network."
  - Added validation router is attached to the external network.

    Verifying that the external network's ID is the same as the 'network_id'
    value in router.external_gateway_info.

    JIRA: SNAPS-145

    Change-Id: I60795c69679f6e439e6e102115e228a65572db52
    Signed-off-by: spisarski <s.pisarski@cablelabs.com>

diff --git a/docs/submodules/snaps b/docs/submodules/snaps
index d336b42..63ee8af 160000 (submodule)
--- a/docs/submodules/snaps
+++ b/docs/submodules/snaps
@@ -1 +1 @@
-Subproject commit d336b42e1476f05dedad3f6e6653f73987154c87
+Subproject commit 63ee8af859678fdf7b82225d5bf40bddef90c0b3