Prepare prerelease 0.7.2-alpha2

[devcrocod]

Bump version to 0.7.2-alpha2

Motivation and Context

New prerelease version with signing fixes

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Documentation update

Checklist

• I have read the MCP Documentation
• My code follows the repository's style guidelines
• New and existing tests pass locally
• I have added appropriate error handling
• I have added or updated documentation as needed

[Copilot]

Pull Request Overview

This PR bumps the version from 0.7.2-alpha1 to 0.7.2-alpha2 for a new prerelease that includes signing fixes.

• Updates the MCP Kotlin version to 0.7.2-alpha2

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