Update git submodules

* Update docs/submodules/releng from branch 'master'
  to 957053910a3b93d5e7dc56a15e68f1a3803a099a
  - Remove the use of tox-pip-version

    It's fully deprecated and breaks vs latest py versions.
    Please rather use the pip flag --use-deprecated=legacy-resolver

    Change-Id: I927d52a253ba9cc571c11210c2566acbe47a075a
    Signed-off-by: Cédric Ollivier <cedric.ollivier@orange.com>

diff --git a/docs/submodules/releng b/docs/submodules/releng
index cbe5cbe..9570539 160000 (submodule)
--- a/docs/submodules/releng
+++ b/docs/submodules/releng
@@ -1 +1 @@
-Subproject commit cbe5cbeb43cdbc7259027410230bb3abb82a94c4
+Subproject commit 957053910a3b93d5e7dc56a15e68f1a3803a099a