Update git submodules

* Update docs/submodules/releng from branch 'master'
  - xci: Make centos jobs non-voting for promotion

    Change-Id: I981b115bc37f034db991667a29f0ce66b239cbdf
    Signed-off-by: Fatih Degirmenci <fdegir@gmail.com>

diff --git a/docs/submodules/releng b/docs/submodules/releng
index ac161e3..1b2e71a 160000 (submodule)
--- a/docs/submodules/releng
+++ b/docs/submodules/releng
@@ -1 +1 @@
-Subproject commit ac161e386f7b903af5b328147c170b0deecf7aa3
+Subproject commit 1b2e71ae3cb3ce15e87154e4337b9489167cfb53