Update git submodules

* Update docs/submodules/yardstick from branch 'master'
  - Merge "[docs] Fix links to remove references to submodules"
  - [docs] Fix links to remove references to submodules

    All references to submodules must be removed for docs to
    work going forward.

    Can be tested once your project has a local tox file

    Change-Id: Id74581cc584f70ae0b31e31c9dd91593c7be6615
    Signed-off-by: Aric Gardner <agardner@linuxfoundation.org>

diff --git a/docs/submodules/yardstick b/docs/submodules/yardstick
index 8fad21b..472eede 160000 (submodule)
--- a/docs/submodules/yardstick
+++ b/docs/submodules/yardstick
@@ -1 +1 @@
-Subproject commit 8fad21bad150b0c80430af6e40b55f627b4c72eb
+Subproject commit 472eede691468c8b78ab2e16fef43dc3e7e8dae1