Update git submodules

* Update docs/submodules/functest from branch 'master'
  - Merge "Fix Dockerfile.aarch64"
  - Fix Dockerfile.aarch64

    Bugfix for error:
    https://build.opnfv.org/ci/view/functest/job/functest-docker-build-arm-push-master/99/console

    Change-Id: I04b45c05d4bb48c9b5b55050addce707177abcd4
    Signed-off-by: Linda Wang <wangwulin@huawei.com>

diff --git a/docs/submodules/functest b/docs/submodules/functest
index 034e929..18745da 160000 (submodule)
--- a/docs/submodules/functest
+++ b/docs/submodules/functest
@@ -1 +1 @@
-Subproject commit 034e9297da1e9fdf82cf900776dddf252e879d29
+Subproject commit 18745da8f335fe3049ffdd5acdafb5848981a1c9