Update git submodules

* Update docs/submodules/yardstick from branch 'master'
  - Merge "Kubernetes (k8s) support"
  - Kubernetes (k8s) support

    JIRA: YARDSTICK-682

    We decide to support k8s in E release.
    We need to discuss with openretriver team and then rewrite the ping
    test case under k8s as the first step.

    Change-Id: I3f81ebca8de5c1f3a8b7d42581cd7342dc320239
    Signed-off-by: chenjiankun <chenjiankun1@huawei.com>

diff --git a/docs/submodules/yardstick b/docs/submodules/yardstick
index 90e4075..0477602 160000 (submodule)
--- a/docs/submodules/yardstick
+++ b/docs/submodules/yardstick
@@ -1 +1 @@
-Subproject commit 90e407589014ecba0719fc123ed2e8b2bf86309c
+Subproject commit 04776024ae7a404c2987e842fe725589a56600dd