Update git submodules

* Update docs/submodules/yardstick from branch 'master'
  - Merge "Replace assertEqual(x, True|False) with assert[True|False](x)"
  - Replace assertEqual(x, True|False) with assert[True|False](x)

    Change-Id: Id19df79b4d27aab1a83d8350ce6395e87c13472b
    JIRA: YARDSTICK-903
    Signed-off-by: Emma Foley <emma.l.foley@intel.com>

diff --git a/docs/submodules/yardstick b/docs/submodules/yardstick
index e6b6f6f..d2f8983 160000 (submodule)
--- a/docs/submodules/yardstick
+++ b/docs/submodules/yardstick
@@ -1 +1 @@
-Subproject commit e6b6f6fca60322f57329d1c93a01c88c3c81b62c
+Subproject commit d2f89835fa08f88f0100dae2996c49302ee25614