Update git submodules

* Update docs/submodules/releng from branch 'master'
  - Merge "Add missing PS1 var"
  - Add missing PS1 var

    Change-Id: I0d6b8525cc12bb71852a8aeeb67cbc37d0456bcb
    Signed-off-by: Yolanda Robla <yroblamo@redhat.com>

diff --git a/docs/submodules/releng b/docs/submodules/releng
index 3acad62..4cd5733 160000 (submodule)
--- a/docs/submodules/releng
+++ b/docs/submodules/releng
@@ -1 +1 @@
-Subproject commit 3acad6212235cc9409713e838e6833c65c19fd2a
+Subproject commit 4cd5733f55a46acd1025589a7e904fb4c89fad7a