Update git submodules

* Update docs/submodules/yardstick from branch 'master'
  - Merge "update ci pod in the test suite according to Fraser"
  - update ci pod in the test suite according to Fraser

    Change-Id: I999b44cc4e0ec1029c6efca224e691298a007689
    Signed-off-by: rexlee8776 <limingjiang@huawei.com>

diff --git a/docs/submodules/yardstick b/docs/submodules/yardstick
index 3a8305d..0b21b64 160000 (submodule)
--- a/docs/submodules/yardstick
+++ b/docs/submodules/yardstick
@@ -1 +1 @@
-Subproject commit 3a8305d3cc4dde0bda09285c8e133529c3c0958a
+Subproject commit 0b21b6484cc383f2a78aa9d5db1d41189d84ca3d