Update git submodules

* Update docs/submodules/yardstick from branch 'stable/fraser'
  - Merge "Add "host_name_separator" variable to Context class" into stable/fraser
  - Add "host_name_separator" variable to Context class

    This feature will provide Kubernetes context the ability to handle the
    context name inside the class itself, providing to the developer an
    abstraction of the possible naming limitations in Kubernetes. E.g.:
    "dot" character in Pod names is no allowed [1].

    [1] https://github.com/fabric8io/fluent-plugin-kubernetes_metadata_filter/issues/58

    JIRA: YARDSTICK-1188

    Change-Id: I82121f970b550170357a443b6340be7900602a57
    Signed-off-by: Rodolfo Alonso Hernandez <rodolfo.alonso.hernandez@intel.com>
    (cherry picked from commit a2ee61016721386b40caa4e2d72f61be8adec94a)

diff --git a/docs/submodules/yardstick b/docs/submodules/yardstick
index cd14105..65b073e 160000 (submodule)
--- a/docs/submodules/yardstick
+++ b/docs/submodules/yardstick
@@ -1 +1 @@
-Subproject commit cd14105fa5a7b37e9acd0a968691da9e41d981bc
+Subproject commit 65b073e55618513633f11111ba9a2ced577d1d31