go : support "auto" as an option when set language (#462)

Co-authored-by: Ming <ming@localhost>

bindings/go/params.go

@@ -49,6 +49,10 @@ func (p *Params) SetSpeedup(v bool) {
 
 // Set language id
 func (p *Params) SetLanguage(lang int) error {
+	if lang == -1 {
+		p.language = nil
+		return nil
+	}
 	str := C.whisper_lang_str(C.int(lang))
 	if str == nil {
 		return ErrInvalidLanguage