Set an expiration date for individual user budgets

Why it matters

This update gives administrators more granular control over Copilot spending. Previously, budgets might have been perpetual or required manual removal. Setting expiration dates allows for temporary project-based access or trial periods. This affects organizations managing multiple users and budgets. While other AI coding assistants may offer similar budget management, this specific feature enhances GitHub Copilot's enterprise appeal by simplifying cost management for time-limited initiatives. Future developments might include automated budget renewal options or integration with project management tools.