wasi-http has advanced to phase 3

Author: Pat Hickey

README.md

@@ -4,7 +4,7 @@ A proposed [WebAssembly System Interface](https://github.com/WebAssembly/WASI) A
 
 ### Current Phase
 
-wasi-http is currently in [Phase 2](https://github.com/WebAssembly/WASI/blob/main/Proposals.md#phase-2---proposed-spec-text-available-cg--wg).
+wasi-http is currently in [Phase 3](https://github.com/WebAssembly/WASI/blob/main/Proposals.md#phase-3---implementation-phase-cg--wg)
 
 ### Champions