Update git submodules

* Update docs/submodules/releng from branch 'master'
  - Merge "securedlab: Use Pharos git sub for PDF validation"
  - securedlab: Use Pharos git sub for PDF validation

    - drop obsolete file pattern matching.
    - drop duplicate check-jinja2.sh from releng, use securedlab script;

    While at it, s/danube/euphrates/ to enable stable/E verify.

    Depends-on: I9d6807f3d24cee8d9a03955112a8c179d9ea7d14

    Change-Id: Ia88140d872f2b64ff013f22ef0f43bd2cb31bd4f
    Signed-off-by: Alexandru Avadanii <Alexandru.Avadanii@enea.com>

diff --git a/docs/submodules/releng b/docs/submodules/releng
index 1b4a945..6f488fb 160000 (submodule)
--- a/docs/submodules/releng
+++ b/docs/submodules/releng
@@ -1 +1 @@
-Subproject commit 1b4a9451bbb39caf636e9ffa1b10feba3c3e2c7a
+Subproject commit 6f488fb6b767d72ca1089d0720928fefce357fab