Use the right type when calling ykpiv_get_serial (C.uint32_t vs C.uint)

ykpiv.go

@@ -203,7 +203,7 @@ func (y Yubikey) Version() ([]byte, error) {
 }
 
 func (y Yubikey) Serial() (uint32, error) {
-	serial := C.uint(0)
+	serial := C.uint32_t(0)
 	if err := getError(C.ykpiv_get_serial(y.state, &serial), "get_serial"); err != nil {
 		return 0, err
 	}