Backwards-compatibility in Cloudflare Workers

Introduced the concept of 'compatibility dates' for Cloudflare Workers. This allows for the introduction of backwards-incompatible changes to the Workers Runtime by providing developers with a mechanism to opt-in to these changes. Developers can set a compatibility date in their project metadata, and the runtime will selectively apply new behaviors based on this date. This addresses the challenge of fixing bugs or improving existing functionality without breaking existing production applications.