Update git submodules

* Update docs/submodules/sfc from branch 'stable/euphrates'
  - Release notes update

    This is an update of the release notes for the Euphrates release

    Change-Id: Ia74839aceb53f6a647b4695c0cc3f7cf8d8e8282
    Signed-off-by: Manuel Buil <mbuil@suse.com>
    (cherry picked from commit 53798427e7cf6f4c709ae2c03bd305b920cbb773)

diff --git a/docs/submodules/sfc b/docs/submodules/sfc
index 5e51b20..b91a28c 160000 (submodule)
--- a/docs/submodules/sfc
+++ b/docs/submodules/sfc
@@ -1 +1 @@
-Subproject commit 5e51b205160f869b94ab2e83815413950ae76631
+Subproject commit b91a28cc827617e8fde34a52d4e8ab0255b663a8