Update git submodules

* Update docs/submodules/yardstick from branch 'stable/euphrates'
  - Docs: update new test cases in release note

    Change-Id: Ie5ff6fe4f867ce68a33a3a857d8d051ba0020395
    Signed-off-by: JingLu5 <lvjing5@huawei.com>
    (cherry picked from commit b463496e6515a42e29b814194d8b19ed2f639239)

diff --git a/docs/submodules/yardstick b/docs/submodules/yardstick
index bcba6eb..479a571 160000 (submodule)
--- a/docs/submodules/yardstick
+++ b/docs/submodules/yardstick
@@ -1 +1 @@
-Subproject commit bcba6eb6000a78de24b18186b66569a51e8e4c3b
+Subproject commit 479a571e913f29178990458ad02fb62cd6cb843e