fix: correct http status

matrixbot.go

@@ -75,7 +75,6 @@ func (bot *MatrixBot) HandleFunc(command string, handler func(bot *MatrixBot, no
 
 func (bot *MatrixBot) Serve(endpoint string) {
 	http.HandleFunc("/healthz", func(writer http.ResponseWriter, request *http.Request) {
-		writer.WriteHeader(200)
 		_, _ = io.WriteString(writer, "OK\n")
 	})
 	http.HandleFunc(bot.pushUrl.RequestURI(), func(writer http.ResponseWriter, request *http.Request) {