Update spec URL to wintertc.org (#84)

Author: andreubotella

index.bs

@@ -4,7 +4,7 @@ Shortname: minimum-common-api
 Group: wintercg
 Status: w3c/CG-DRAFT
 Level: none
-URL: https://min-common-api.proposal.wintercg.org/
+URL: https://min-common-api.proposal.wintertc.org/
 Repository: https://github.com/wintercg/proposal-minimum-common-api
 Editor: James M Snell, Cloudflare https://cloudflare.com/, [email protected]
 Abstract: Minimum Common Web Platform API for Non-Browser ECMAScript-based runtimes.