update wasm go sdk to tinygo 0.28.1 (#462)

plugins/wasm-go/extensions/waf/init_tinygo.go

@@ -1,14 +1,30 @@
+// Copyright The OWASP Coraza contributors
+// SPDX-License-Identifier: Apache-2.0
+
 //go:build tinygo
 
 package main
 
-import _ "github.com/wasilibs/nottinygc"
+import (
+	"unsafe"
+)
 
-// Compiled by nottinygc for delayed free but Envoy doesn't stub it yet,
-// luckily nottinygc doesn't actually call the function, so it's fine to
-// stub it out.
+// Some host functions that are not implemented by Envoy end up getting imported anyways
+// by code that gets compiled but not executed at runtime. Because we know they are not
+// executed, we can stub them out to allow functioning on Envoy. Note, these match the
+// names and signatures of wasi-libc, used by TinyGo, not WASI ABI. Review these exports when either
+// the minimum supported version of Envoy changes or the maximum version of TinyGo.
 
-//export sched_yield
-func sched_yield() int32 {
-	return 0
+// fdopendir is re-exported to avoid TinyGo 0.28's import of wasi_snapshot_preview1.fd_readdir.
+//
+//export fdopendir
+func fdopendir(fd int32) unsafe.Pointer {
+	return nil
+}
+
+// readdir is re-exported to avoid TinyGo 0.28's import of wasi_snapshot_preview1.fd_readdir.
+//
+//export readdir
+func readdir(unsafe.Pointer) unsafe.Pointer {
+	return nil
 }