Update git submodules

* Update docs/submodules/releng from branch 'master'
  - Merge "Remove OPNFV Docs Euphrates Jobs"
  - Remove OPNFV Docs Euphrates Jobs

    The release is now two past and we don't need to continue building these
    docs.

    Change-Id: I072d22b69d73c06245a4efcf14661e0c7acacefc
    Signed-off-by: Trevor Bramwell <tbramwell@linuxfoundation.org>

diff --git a/docs/submodules/releng b/docs/submodules/releng
index 9c1f49b..08ba3bc 160000 (submodule)
--- a/docs/submodules/releng
+++ b/docs/submodules/releng
@@ -1 +1 @@
-Subproject commit 9c1f49b94c005a48f57a30f2b4303793f52a2d84
+Subproject commit 08ba3bca0a012275ae72920f2be6719c7cf357d7