Update git submodules

* Update docs/submodules/releng from branch 'master'
  - Merge "opnfv-lint: Enable yamllint for Fuel & Armband"
  - opnfv-lint: Enable yamllint for Fuel & Armband

    Change-Id: Iaccfa0df8f9f282a54712f61489af3029a91d44b
    Signed-off-by: Alexandru Avadanii <Alexandru.Avadanii@enea.com>

diff --git a/docs/submodules/releng b/docs/submodules/releng
index dc30446..2a51732 160000 (submodule)
--- a/docs/submodules/releng
+++ b/docs/submodules/releng
@@ -1 +1 @@
-Subproject commit dc304463a3b26edb4abf24cb7292750400c42466
+Subproject commit 2a51732ab54f286053cf7fc3c84bbac1662317a8