Update git submodules

* Update docs/submodules/holmes/rule-management.git from branch 'master'
  to ad6dd88c5d5aa64aa624e5613fd584b5f2a5540f
  - Migrate holmes-rule-management docs

    Merging this will create
    https://onap-holmes-rule-management.readthedocs.io
    This build will run in parallel
    to the current docs generation method
    until we are ready to cut over.

    Issue-ID: CIMAN-364
    Signed-off-by: Jessica Wagantall <jwagantall@linuxfoundation.org>
    Change-Id: Icce5e84c600441ac631bc2294dfbf3cfe8efc6f1

diff --git a/docs/submodules/holmes/rule-management.git b/docs/submodules/holmes/rule-management.git
index 49f817d..ad6dd88 160000 (submodule)
--- a/docs/submodules/holmes/rule-management.git
+++ b/docs/submodules/holmes/rule-management.git
@@ -1 +1 @@
-Subproject commit 49f817de0db1f1e5e310990b8a44f4ab18650361
+Subproject commit ad6dd88c5d5aa64aa624e5613fd584b5f2a5540f