Update git submodules

* Update docs/submodules/ipv6 from branch 'master'
  - Fix format

    Change-Id: I9b6533c68db44ca9c57a666d878e1594f9b5c32a
    Signed-off-by: Bin Hu <bh526r@att.com>

diff --git a/docs/submodules/ipv6 b/docs/submodules/ipv6
index c273998..29b59d2 160000 (submodule)
--- a/docs/submodules/ipv6
+++ b/docs/submodules/ipv6
@@ -1 +1 @@
-Subproject commit c27399813382524aa7b0d527463f3f91952dc384
+Subproject commit 29b59d2aa341d29d0711f57b64030448af55fdae