Update git submodules

* Update docs/submodules/policy/apex-pdp.git from branch 'master'
  to 50b84774797677791fb2111cf97b9f2ff65cb3e2
  - Changes to send pdp status messages

    1) Adding handlers to create and send pdp status messages from apex-pdp.
    2) Changes to read initial pdp status parameters from configuration
    file.
    3) Adding test cases.

    Change-Id: Id2d1caa8abc124865a9ef8fbfe4d9f751e4491b5
    Issue-ID: POLICY-1452
    Signed-off-by: a.sreekumar <ajith.sreekumar@est.tech>

diff --git a/docs/submodules/policy/apex-pdp.git b/docs/submodules/policy/apex-pdp.git
index ab4cba7..50b8477 160000 (submodule)
--- a/docs/submodules/policy/apex-pdp.git
+++ b/docs/submodules/policy/apex-pdp.git
@@ -1 +1 @@
-Subproject commit ab4cba7d37f41eddbf3ab040f04afe18c6630777
+Subproject commit 50b84774797677791fb2111cf97b9f2ff65cb3e2