Update git submodules

* Update docs/submodules/releng from branch 'master'
  - Merge "Add Doctor maintenance job"
  - Add Doctor maintenance job

    Change-Id: I1d5d83df75f25ae3f54a660e5a0cba4290a1510b
    Signed-off-by: Tomi Juvonen <tomi.juvonen@nokia.com>

diff --git a/docs/submodules/releng b/docs/submodules/releng
index 1c4cc03..b55046a 160000 (submodule)
--- a/docs/submodules/releng
+++ b/docs/submodules/releng
@@ -1 +1 @@
-Subproject commit 1c4cc0319e5b1c37b9221b776ea264cacf8f1478
+Subproject commit b55046ac8825f81dcd440fa772ba179e172faacc