Fix Service description: NodePort -> ClusterIP

[sredituo]

The documentation currently states "Create a NodePort service" (in the "Key components" section).
However, the provided YAML manifest does not specify type: NodePort, so it defaults to ClusterIP.
I have updated the text to "ClusterIP service".

❯ cat 03-service.yaml
apiVersion: v1
kind: Service
metadata:
  namespace: game-2048
  name: service-2048
spec:
  ports:
    - port: 80
      targetPort: 80
      protocol: TCP
  selector:
    app.kubernetes.io/name: app-2048

❯ kubectl apply -f 03-service.yaml
service/service-2048 created

❯ kubectl get service -n game-2048
NAME           TYPE        CLUSTER-IP       EXTERNAL-IP   PORT(S)   AGE
service-2048   ClusterIP   10.100.255.129   <none>        80/TCP    96s

[aws-amplify-us-east-1]

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