Update git submodules

* Update docs/submodules/functest from branch 'stable/euphrates'
  - Conform with Docker ARCH names

    It switches Docker tags:
      - x86_64 -> amd64
      - aarch64 -> arm64

    Conflicts:
        .travis.yml
        build.sh

    Change-Id: I05575dd728e7502a891a3ee3015f81ac8e3f7a92
    Signed-off-by: Cédric Ollivier <cedric.ollivier@orange.com>
    (cherry picked from commit a8acc48148313229b4e6771374ece9256d75b26c)

diff --git a/docs/submodules/functest b/docs/submodules/functest
index 188f633..fed7233 160000 (submodule)
--- a/docs/submodules/functest
+++ b/docs/submodules/functest
@@ -1 +1 @@
-Subproject commit 188f6330f4c941e0b582116f9161b7b82528e2a7
+Subproject commit fed72336e3b50b8441f233a2f122e482ee83ae8c