Add the policy-apex-pdp docker image from Nordix temporarily

The policy-apex-pdp docker image has not been released in ONAP but is
needed for the D release of OSC. Hence, the docker image will be
temporarily stored in Nordix.

Change-Id: I1c94b8e48b2dd07e8a7a816b554b054761cccada
Issue-ID: NONRTRIC-547
Signed-off-by: RehanRaza <muhammad.rehan.raza@est.tech>
diff --git a/solution/integration/smo/onap-policy/docker-compose.yml b/solution/integration/smo/onap-policy/docker-compose.yml
index e129afd..17f2435 100644
--- a/solution/integration/smo/onap-policy/docker-compose.yml
+++ b/solution/integration/smo/onap-policy/docker-compose.yml
@@ -160,7 +160,7 @@
        - nonrtric
        - smo
    apex-pdp:
-      image: nexus3.onap.org:10001/onap/policy-apex-pdp:latest
+      image: registry.nordix.org/onap/policy-apex-pdp:2.6.0-SNAPSHOT
       container_name: policy-apex-pdp
       depends_on:
        - mariadb