[shotwell] Fix avif detection

[Jens Georg <jensgeorg src gnome org>]

commit 5e21249fd9e5f210e8e333298a965dda7f3b5162
Author: Jens Georg <mail jensge org>
Date:   Tue Apr 5 07:21:22 2022 +0000

    Fix avif detection

 src/photos/PhotoFileFormat.vala | 1 +
 1 file changed, 1 insertion(+)
---
diff --git a/src/photos/PhotoFileFormat.vala b/src/photos/PhotoFileFormat.vala
index c839b1c5..fbb72d4b 100644
--- a/src/photos/PhotoFileFormat.vala
+++ b/src/photos/PhotoFileFormat.vala
@@ -233,6 +233,7 @@ public enum PhotoFileFormat {
                 return PhotoFileFormat.GIF;
 
             case "heif/avif":
+            case "avif":
                 return PhotoFileFormat.AVIF;
 
             default: