Updated README to use 'resources' instead of 'bases' in overlays exam…

…ple.

Kubernetes v1.21 upgrade kustomize-in-kubectl to v4.0.5. kubernetes/kubernetes#98946
So I think this example could update back to use resources instead of bases?

examples/helloWorld/README.md

@@ -148,7 +148,7 @@ commonLabels:
   org: acmeCorporation
 commonAnnotations:
   note: Hello, I am staging!
-bases:
+resources:
 - ../../base
 patchesStrategicMerge:
 - map.yaml
@@ -189,7 +189,7 @@ commonLabels:
   org: acmeCorporation
 commonAnnotations:
   note: Hello, I am production!
-bases:
+resources:
 - ../../base
 patchesStrategicMerge:
 - deployment.yaml