[Hotfix][tools] Include Helm chart in change-version script

[xxubai]

Why are the changes needed?

The tools/change-version.sh script currently updates only Maven POM files. As a result, the Helm chart appVersion can remain stale after a project version change, requiring a follow-up hotfix to align the chart with the released application version.

The root cause is that the script searches only for pom.xml files and does not include the Helm chart as a project-version carrier.

Brief change log

• Update the Helm chart appVersion together with Maven POM versions.
• Keep the release guide's embedded script example in sync with the implementation.

How was this patch tested?

• Add some test cases that check the changes thoroughly including negative and positive cases if possible

• Add screenshots for manual tests if appropriate

• Run test locally before making a pull request

  • bash -n tools/change-version.sh
  • Isolated fixture verification for POM and Helm chart version replacement, including idempotency
  • ./mvnw validate
  • helm lint charts/amoro

Documentation

• Does this pull request introduce a new feature? no
• If yes, how is the feature documented? not applicable