Update git submodules

* Update docs/submodules/releng from branch 'master'
  to 0c37a675a3df3dc3091c7bd27a270b3bfc403f71
  - Update golang to 1.15

    Change-Id: I91d937bd4e07f3b8d371417bc9698a5ecdab6d4a
    Signed-off-by: Cédric Ollivier <cedric.ollivier@orange.com>

diff --git a/docs/submodules/releng b/docs/submodules/releng
index 0c108ad..0c37a67 160000 (submodule)
--- a/docs/submodules/releng
+++ b/docs/submodules/releng
@@ -1 +1 @@
-Subproject commit 0c108ad88bad281eaea677419969d5dc0e641517
+Subproject commit 0c37a675a3df3dc3091c7bd27a270b3bfc403f71