Add WinterTC baseline as a target

[reesericci]

WinterTC is the global base target API for serverless functions and other "web interoperable server runtimes." I think it would serve esbuild to support WinterTC's "Minimum Common API," (optionally supporting the proposed Sockets and CLI APIs) as an output target to have a common target to build for a variety of WinterTC-compatible runtimes.

https://wintertc.org/work

https://min-common-api.proposal.wintertc.org

[evanw]

Sorry, I don't understand. I don't see anything on https://min-common-api.proposal.wintertc.org/ that's relevant to esbuild. These are all about APIs, which is not something that esbuild's target setting is concerned with. The target setting is only concerned with syntax features, not APIs. It does not automatically add polyfills for new APIs. That is something I consider to be out of esbuild's scope.