[Batch] Data Plane v15.1.0 GA Release

[cRui861]

Description

This is the GA release of the Batch data plane Python SDK.

All SDK Contribution checklist:

• The pull request does not introduce [breaking changes]
• CHANGELOG is updated for new features, bug fixes or other significant changes.
• I have read the contribution guidelines.

General Guidelines and Best Practices

• Title of the pull request is clear and informative.
• There are a small number of commits, each of which have an informative message. This means that previously merged commits do not appear in the history of the PR. For more information on cleaning up the commits in your PR, see this page.

Testing Guidelines

• Pull request includes test coverage for the included changes.

[Copilot]

Pull request overview

GA release prep for the azure-batch data plane SDK by moving the package from beta to stable and aligning versioning + release notes accordingly.

Changes:

• Promote package classifier from Beta to Production/Stable.
• Bump package version from 15.1.0b3 to 15.1.0.
• Add a 15.1.0 GA entry to the changelog indicating no changes since the last beta.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated no comments.

File	Description
sdk/batch/azure-batch/pyproject.toml	Updates Trove classifier to mark the package as Production/Stable (GA).
sdk/batch/azure-batch/azure/batch/_version.py	Sets the library version to the GA version 15.1.0.
sdk/batch/azure-batch/CHANGELOG.md	Adds the 15.1.0 GA release entry and notes that it matches the last beta.