Upyo 0.3.0: Multi-provider resilience and deployment flexibility

Upyo 0.3.0 introduces three new transports designed to enhance email delivery capabilities and reliability. The update focuses on multi-provider support and flexible deployment options. The new pool transport, via the `@upyo/pool` package, combines multiple email providers with routing strategies like round-robin, weighted distribution, and priority-based routing, ensuring high availability and cost optimization. Additionally, the `@upyo/resend` package integrates Resend, an email service provider known for its developer-friendly approach and intelligent batch optimization. For those needing self-hosting options, the `@upyo/plunk` package supports Plunk, offering both cloud-hosted and Docker-based self-hosted deployments. These new transports maintain Upyo's consistent API design, ensuring they can be easily integrated into existing workflows. This release expands Upyo's utility by providing more robust and adaptable email delivery solutions.