Bug 1980 fixed

Added the `yaml_format` argument to the `status_kdu` abstract method of
the class `K8sConnector`, and changed the corresponding Helm connectors
methods accordingly, while maintaining backward compatibility

Change-Id: Ic78c951825b7654ccf8246c4fe1fc4d488221bfc
Signed-off-by: Pedro Escaleira <escaleira@av.it.pt>
diff --git a/n2vc/k8s_conn.py b/n2vc/k8s_conn.py
index a4b98db..ef4f5f2 100644
--- a/n2vc/k8s_conn.py
+++ b/n2vc/k8s_conn.py
@@ -22,6 +22,7 @@
 
 import abc
 import asyncio
+from typing import Union
 import time
 
 from n2vc.loggable import Loggable
@@ -358,7 +359,9 @@
         """
 
     @abc.abstractmethod
-    async def status_kdu(self, cluster_uuid: str, kdu_instance: str) -> str:
+    async def status_kdu(
+        self, cluster_uuid: str, kdu_instance: str, yaml_format: str
+    ) -> Union[str, dict]:
         """
         This call would retrieve tha current state of a given KDU instance. It would be
         would allow to retrieve the _composition_ (i.e. K8s objects) and _specific
@@ -367,6 +370,8 @@
 
         :param cluster_uuid: UUID of a K8s cluster known by OSM
         :param kdu_instance: unique name for the KDU instance
+        :param yaml_format: if the return shall be returned as an YAML string or as a
+                                dictionary
         :return: If successful, it will return the following vector of arguments:
         - K8s `namespace` in the cluster where the KDU lives
         - `state` of the KDU instance. It can be: