Update git submodules

* Update docs/submodules/dovetail from branch 'master'
  - Updating the container tags of the test projects

    Setting the container versions of the test tools to a specific release
    tag.

    Change-Id: I3422be006ff80035cecc9ec22eba50b02ed97be6
    Signed-off-by: Georg Kunz <georg.kunz@ericsson.com>

diff --git a/docs/submodules/dovetail b/docs/submodules/dovetail
index 4413f06..a5f91fb 160000 (submodule)
--- a/docs/submodules/dovetail
+++ b/docs/submodules/dovetail
@@ -1 +1 @@
-Subproject commit 4413f0693b34158af4a4fd86eca5762e42f232ed
+Subproject commit a5f91fbd49474a88d6a9c92e9da36d2cf20804ac