Update git submodules

* Update plugins/singleusergroup from branch 'master'
  to b39f37b4be2d62e2e0b87b112a0acdfd7712777b
  - singleusergroup_tests: Move plugin dependency from deps to runtime_deps
    
    The singleusergroup__plugin dependency is incorrectly declared as
    compiled dependency, even though it is only runtime dependency. This
    was flagged by unused_deps utility.
    
    Change-Id: I89b8c94bc44673d7bdfd69c6ca35383f01d48ee6
    
diff --git a/plugins/singleusergroup b/plugins/singleusergroup
index 3c4e63c..b39f37b 160000
--- a/plugins/singleusergroup
+++ b/plugins/singleusergroup
@@ -1 +1 @@
-Subproject commit 3c4e63c40937a9b47c9536851ae4c286ec94db3f
+Subproject commit b39f37b4be2d62e2e0b87b112a0acdfd7712777b