Make ResourceService API more flexible in parameter

Change-Id: Ic8b803cc6ae3b2798de525bfd6545ac5c57e8fdd
diff --git a/core/api/src/test/java/org/onosproject/net/resource/MockResourceService.java b/core/api/src/test/java/org/onosproject/net/resource/MockResourceService.java
index f5f884b..52236b3 100644
--- a/core/api/src/test/java/org/onosproject/net/resource/MockResourceService.java
+++ b/core/api/src/test/java/org/onosproject/net/resource/MockResourceService.java
@@ -38,7 +38,7 @@
     private final Map<Resource, ResourceConsumer> assignment = new HashMap<>();
 
     @Override
-    public List<ResourceAllocation> allocate(ResourceConsumer consumer, List<Resource> resources) {
+    public List<ResourceAllocation> allocate(ResourceConsumer consumer, List<? extends Resource> resources) {
         assignment.putAll(
                 resources.stream().collect(Collectors.toMap(Function.identity(), x -> consumer))
         );