Update git submodules

* Update docs/submodules/releng from branch 'master'
  - Merge "Add support for tox in SFC project jobs"
  - Add support for tox in SFC project jobs

    Depends-On: https://gerrit.opnfv.org/gerrit/#/c/58649/

    Change-Id: I4b39c6fd8e70fe40c68e5b2d7043ee522583290b
    Signed-off-by: Dimitrios Markou <mardim@intracom-telecom.com>

diff --git a/docs/submodules/releng b/docs/submodules/releng
index 6df5a5f..0713907 160000 (submodule)
--- a/docs/submodules/releng
+++ b/docs/submodules/releng
@@ -1 +1 @@
-Subproject commit 6df5a5f564dc77fe43fbccb84860d61c06fdf5b9
+Subproject commit 07139071a8d3e7d0207ccac05b24b84bf11f712a