Update git submodules

* Update docs/submodules/releng from branch 'master'
  to 0a2dfdffb822f822e041085a8e32fe4f87d55f87
  - Merge "Update to python 3.7 and alpine 3.10"
  - Update to python 3.7 and alpine 3.10

    Change-Id: Id800208e148190ee10e4cfcb2a48a2dff00c35a7
    Signed-off-by: Cédric Ollivier <cedric.ollivier@orange.com>

diff --git a/docs/submodules/releng b/docs/submodules/releng
index 3aad5c1..0a2dfdf 160000 (submodule)
--- a/docs/submodules/releng
+++ b/docs/submodules/releng
@@ -1 +1 @@
-Subproject commit 3aad5c124e77b44b513727281e471d7083eb190b
+Subproject commit 0a2dfdffb822f822e041085a8e32fe4f87d55f87