Revert "refactor: remove unneeded implementation of NamespaceChangeable"

This reverts commit 8a7b04c.

Author: metacosm

operator-framework-core/src/main/java/io/javaoperatorsdk/operator/processing/dependent/kubernetes/KubernetesDependentResourceConfig.java

@@ -2,6 +2,7 @@
 
 import java.util.Set;
 
+import io.javaoperatorsdk.operator.api.config.NamespaceChangeable;
 import io.javaoperatorsdk.operator.api.reconciler.Constants;
 import io.javaoperatorsdk.operator.api.reconciler.ResourceDiscriminator;
 import io.javaoperatorsdk.operator.processing.event.source.filter.GenericFilter;
@@ -11,7 +12,7 @@
 
 import static io.javaoperatorsdk.operator.api.reconciler.Constants.NO_VALUE_SET;
 
-public class KubernetesDependentResourceConfig<R> {
+public class KubernetesDependentResourceConfig<R> implements NamespaceChangeable {
 
   private Set<String> namespaces = Constants.SAME_AS_CONTROLLER_NAMESPACES_SET;
   private String labelSelector = NO_VALUE_SET;
@@ -88,7 +89,12 @@ public ResourceDiscriminator getResourceDiscriminator() {
     return resourceDiscriminator;
   }
 
-  @SuppressWarnings("unused")
+  @Override
+  public void changeNamespaces(Set<String> namespaces) {
+    setNamespaces(namespaces);
+    this.namespacesWereConfigured = true;
+  }
+
   protected void setNamespaces(Set<String> namespaces) {
     if (!wereNamespacesConfigured() && namespaces != null && !namespaces.isEmpty()) {
       this.namespaces = namespaces;