Update git submodules

* Update docs/submodules/policy/engine.git from branch 'master'
  to 6a4266db5ce20717f787dff410839281e92bb081
  - update dependencies from policy/models
    
    Now pointing to policy/models for yaml and other dependencies.
    
    Issue-ID: POLICY-1264
    Change-Id: I440d18425e46ec91e6d4e7f2cf1571c4d2bbdb6f
    Signed-off-by: Hengye <yehui.wang@est.tech>
    Signed-off-by: Pamela Dragosh <pdragosh@research.att.com>
    
1 file changed