Change the official Lua URL from www.lua.org to lua.org

the file cannot be retrieved because the updated server certificate is
not a wildcard certificate.

fetch.go

@@ -153,6 +153,12 @@ func CmdFetch() {
 			}
 			defer rsp.Body.Close()
 
+			// check status code
+			if rsp.StatusCode != http.StatusOK {
+				eprintf("failed to download %q: %s\n", target.cfg.ReleaseURL, rsp.Status)
+				continue
+			}
+
 			b, err := io.ReadAll(rsp.Body)
 			if err != nil {
 				eprintf("failed to read body: %v\n", err)

main.go

@@ -31,8 +31,8 @@ var (
 		Name:        "lua",
 		RootDir:     filepath.Join(LenvDir, "lua"),
 		VersionFile: filepath.Join(LenvDir, "lua_vers.txt"),
-		ReleaseURL:  "http://www.lua.org/ftp/",
-		DownloadURL: "http://www.lua.org/ftp/",
+		ReleaseURL:  "http://lua.org/ftp/",
+		DownloadURL: "http://lua.org/ftp/",
 	}
 	LuaJitCfg = &TargetConfig{
 		Name:        "luajit",