Update git submodules

* Update docs/submodules/releng from branch 'master'
  - Move back to opnfv/functest-* for alpine containers

    Temporary solutions relied on ollivier/functest-* but
    now opnfv/functest-* are well produced and can be used as official
    reference for CI

    Change-Id: I02b5a03929d5b31df0db2a6c4722edf62b920df9
    Signed-off-by: Morgan Richomme <morgan.richomme@orange.com>

diff --git a/docs/submodules/releng b/docs/submodules/releng
index 20b3130..5283e9d 160000 (submodule)
--- a/docs/submodules/releng
+++ b/docs/submodules/releng
@@ -1 +1 @@
-Subproject commit 20b31307c730a6561107dba6299d3a47dd4c3090
+Subproject commit 5283e9de99b87d74cb5bb28da04b48f17c02a3b6