Update git submodules

* Update docs/submodules/releng from branch 'master'
  - Merge "[docs] Limit git submodule recurse to depth 1"
  - [docs] Limit git submodule recurse to depth 1

    Some projects (e.g. Fuel, Armband) embed their own git submodules,
    which are picked up by Sphinx during RTD verify job, leading to a lot
    of issues (e.g. duplicate labels since Armband includes Fuel as a git
    submodule of its own).

    Change-Id: I771f7c95334fc25c82cc8b14ee2064b043d9e321
    Signed-off-by: Alexandru Avadanii <Alexandru.Avadanii@enea.com>

diff --git a/docs/submodules/releng b/docs/submodules/releng
index 4bc3852..c04f88c 160000 (submodule)
--- a/docs/submodules/releng
+++ b/docs/submodules/releng
@@ -1 +1 @@
-Subproject commit 4bc3852c2aeacef942b8e64e8ba5275ef8e43640
+Subproject commit c04f88ca91b7612c70bcae9c8a70a98d5bd46c6e