Commit 39cc0c1b for libheif

commit 39cc0c1be65757ea2df542e4b72810bcace82b44
Author: Dirk Farin <dirk.farin@gmail.com>
Date:   Fri May 15 02:34:26 2026 +0200

    add missing Go enum

diff --git a/go/heif/heif.go b/go/heif/heif.go
index 4a50bbe1..de483a3c 100644
--- a/go/heif/heif.go
+++ b/go/heif/heif.go
@@ -106,6 +106,7 @@ const (
 	ColorspaceUndefined   = C.heif_colorspace_undefined
 	ColorspaceYCbCr       = C.heif_colorspace_YCbCr
 	ColorspaceRGB         = C.heif_colorspace_RGB
+	ColorspaceCustom      = C.heif_colorspace_custom
 	ColorspaceMonochrome  = C.heif_colorspace_monochrome
 	ColorspaceFilterArray = C.heif_colorspace_filter_array
 	ColorspaceNonvisual   = C.heif_colorspace_nonvisual