[SPARK-52161] Add home, sources, maintainers, keywords metadata to Chart.yaml

[dongjoon-hyun]

What changes were proposed in this pull request?

This PR aims to add the following metadata to Chart.yaml.

• home
• sources
• maintainers
• keywords

Why are the changes needed?

To provide a correct metadata to the users of Helm chart.

Does this PR introduce any user-facing change?

No behavior change.

How was this patch tested?

Manual review by packaging Helm chart and generating index.

$ cd build-tools/helm
$ helm package --sign --key YOUR_KEY --keyring YOUR_KEYRING spark-kubernetes-operator
$ helm repo index .
$ cat index.yaml
apiVersion: v1
entries:
  spark-kubernetes-operator:
  - apiVersion: v2
    appVersion: 0.2.0-SNAPSHOT
    created: "2025-05-15T07:28:59.279471-07:00"
    description: The official Helm chart to deploy Apache Spark, an unified engine
      for large-scale data analytics
    digest: 3b90cca4a6921bccd541c5a3f10be319adc19d50a164b368776adf3736061b12
    home: https://apache.github.io/spark-kubernetes-operator/
    icon: https://spark.apache.org/images/spark-logo.png
    keywords:
    - apache
    - spark
    - sparkapp
    - sparkcluster
    maintainers:
    - email: [email protected]
      name: Apache Spark PMC
    name: spark-kubernetes-operator
    sources:
    - https://github.com/apache/spark-kubernetes-operator/
    type: application
    urls:
    - spark-kubernetes-operator-1.0.0-dev.tgz
    version: 1.0.0-dev
generated: "2025-05-15T07:28:59.278325-07:00"

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

No.

[dongjoon-hyun]

Thank you, @viirya . Merged to main.

[dongjoon-hyun]

BTW, I'm planning to cut v0.2.0 this weekend, @viirya , @peter-toth , @jiangzho , @TQJADE .