[SPARK-52607] Add pi-v1beta1.yaml example

[dongjoon-hyun]

What changes were proposed in this pull request?

This PR aims to add pi-v1beta1.yaml example.

$ diff examples/pi.yaml examples/pi-v1beta1.yaml
15c15
< apiVersion: spark.apache.org/v1
---
> apiVersion: spark.apache.org/v1beta1
18c18
<   name: pi
---
>   name: pi-v1beta1

Why are the changes needed?

To give an example to support old versions.

$ ./gradlew build -x test

$ ./gradlew buildDockerImage

$ helm install spark -f build-tools/helm/spark-kubernetes-operator/values.yaml build-tools/helm/spark-kubernetes-operator/

$ kubectl apply -f examples/pi.yaml

$ kubectl apply -f examples/pi-v1alpha1.yaml

$ kubectl apply -f examples/pi-v1beta1.yaml

$ kubectl get sparkapp
NAME          CURRENT STATE      AGE
pi            ResourceReleased   92s
pi-v1alpha1   ResourceReleased   46s
pi-v1beta1    ResourceReleased   33s

Does this PR introduce any user-facing change?

No.

How was this patch tested?

Manual review because this is an example.

Was this patch authored or co-authored using generative AI tooling?

No.

[dongjoon-hyun]

Thank you, @viirya .

[dongjoon-hyun]

Merged to main.