Version change, changelog update

[ReneOv-MSFT]

Description

• Updated version number
• Updated changelog

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

This PR updates the azure-compute-batch package documentation to reflect a new beta version and adds a corresponding release entry to the changelog.

Changes:

• Bumped the dependency version shown in the README to 1.0.0-beta.6.
• Added a 1.0.0-beta.6 release section to the CHANGELOG with features and breaking changes.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 8 comments.

File	Description
sdk/batch/azure-compute-batch/README.md	Updates the Maven dependency snippet to the new beta version.
sdk/batch/azure-compute-batch/CHANGELOG.md	Adds release notes for 1.0.0-beta.6, including feature additions and breaking changes.