Update git submodules

* Update docs/submodules/yardstick from branch 'master'
  - Merge "Fix setting `flow` configuration in TC yaml"
  - Fix setting `flow` configuration in TC yaml

    The `flow` configuration is not applied to the traffic
    profile if `seed` or `count` option is missing in the
    TC definition.

    - Fix `seed` backward compatibility.

    JIRA: YARDSTICK-1383

    Change-Id: Ic874fb2be1c13009f94eb3a80194bfe81d7a923b
    Signed-off-by: Mytnyk, Volodymyr <volodymyrx.mytnyk@intel.com>

diff --git a/docs/submodules/yardstick b/docs/submodules/yardstick
index 70fa1fc..5b23c7f 160000 (submodule)
--- a/docs/submodules/yardstick
+++ b/docs/submodules/yardstick
@@ -1 +1 @@
-Subproject commit 70fa1fcf237ad41d868d8501c5a49d3331ef6adf
+Subproject commit 5b23c7f12857ea6d47f184046010b467949303e6