Update git submodules

* Update docs/submodules/releng from branch 'master'
  to 5e6970e3eea9c552eb82849fafd5952b7c26bb0a
  - Select 3.6 if iruya

    It conforms with "Select python 3.6 as default" [1].

    [1] https://gerrit.opnfv.org/gerrit/c/functest/+/68471

    Change-Id: Ibc4ae81597ce9ed3d12ab27c6eae796870f6a2d4
    Signed-off-by: Cédric Ollivier <cedric.ollivier@orange.com>

diff --git a/docs/submodules/releng b/docs/submodules/releng
index cc34c44..5e6970e 160000 (submodule)
--- a/docs/submodules/releng
+++ b/docs/submodules/releng
@@ -1 +1 @@
-Subproject commit cc34c4492b58fd217451faacf54359f2b5ad6d06
+Subproject commit 5e6970e3eea9c552eb82849fafd5952b7c26bb0a