Update git submodules

* Update docs/submodules/releng from branch 'master'
  to 20a10fda0c2442d3764ce4bacff33ba23f53d0c2
  - Blacklist k8s_io if K8s v1.21 and newer

    Change-Id: If3d6daa66804f3d2962a8fb3c07e65789d3af002
    Signed-off-by: Cédric Ollivier <cedric.ollivier@orange.com>

diff --git a/docs/submodules/releng b/docs/submodules/releng
index 1952b95..20a10fd 160000 (submodule)
--- a/docs/submodules/releng
+++ b/docs/submodules/releng
@@ -1 +1 @@
-Subproject commit 1952b95f7514adaf51b066c803002127d1ec1687
+Subproject commit 20a10fda0c2442d3764ce4bacff33ba23f53d0c2