Update git submodules

* Update docs/submodules/yardstick from branch 'master'
  - Merge "deepgetitem: try string index before int"
  - deepgetitem: try string index before int

    Change-Id: I3b353c5887db0ebbe33e37db505e72b85167b54e
    Signed-off-by: Ross Brattain <ross.b.brattain@intel.com>

diff --git a/docs/submodules/yardstick b/docs/submodules/yardstick
index d9c0b9e..42c7c49 160000 (submodule)
--- a/docs/submodules/yardstick
+++ b/docs/submodules/yardstick
@@ -1 +1 @@
-Subproject commit d9c0b9e1c2e0a11500fa09c10ba559d4944b720c
+Subproject commit 42c7c490703248d571c9c4dc97610155b32d003a