Update git submodules

* Update docs/submodules/releng from branch 'master'
  to dc2aa77c3082b54b0dd9e376a0287b8224395315
  - Merge "Fix: RTD Gitlab Triggers for Stable branch"
  - Fix: RTD Gitlab Triggers for Stable branch

    Adds a STABLE_BRANCH variable to ensure builds run on merges to
    'stable/*' branches.

    Change-Id: Ib2a72e705600a6a48454acd2b74b35e46d1e9877
    Signed-off-by: Trevor Bramwell <tbramwell@linuxfoundation.org>

diff --git a/docs/submodules/releng b/docs/submodules/releng
index 76d3a46..dc2aa77 160000 (submodule)
--- a/docs/submodules/releng
+++ b/docs/submodules/releng
@@ -1 +1 @@
-Subproject commit 76d3a4640f0ed4317367b9fbc8f2228558cc752e
+Subproject commit dc2aa77c3082b54b0dd9e376a0287b8224395315