📦 docs(README): Update ReadMe for V2.2.0 release

[rajeshgangireddy]

… and performance improvements

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• 🛠️ Fixes # (issue number)

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[Copilot]

Pull Request Overview

This PR updates the README to announce the release of Anomalib v2.2.0, replacing the previous v2.1.0 announcement with new features and improvements.

• Updated version announcement from v2.1.0 to v2.2.0
• Replaced model-focused content with dataset and metrics highlights
• Added performance improvements and memory optimization details

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