[gnome-build-meta] Use testing version of openh264-extension

[Michael Catanzaro <mcatanzaro src gnome org>]

commit ebae9459df992607ccab1f96386fcf41d7528917
Author: Michael Catanzaro <mcatanzaro gnome org>
Date:   Thu Apr 23 12:15:03 2020 -0500

    Use testing version of openh264-extension
    
    This switches our openh264-extension to build from:
    
    https://gitlab.com/freedesktop-sdk/openh264-extension/-/merge_requests/21

 junction.refs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/junction.refs b/junction.refs
index 17e0db44..1a32a223 100644
--- a/junction.refs
+++ b/junction.refs
@@ -3,4 +3,4 @@ projects:
     freedesktop-sdk.bst:
     - ref: freedesktop-sdk-19.08.9-0-g076fe9d30f37224a1bd756a177e33399dad37e8d
     openh264-extension.bst:
-    - ref: 08de6b4315f76b6b09a7cfc9889b61d072cf15ea
+    - ref: b3ccf8d064ac3beaa3359e48057f1bce0c0d97c7