Add entry for AVFilterPicRef interlaced and top_field_first fields

addition.

git-svn-id: file:///var/local/repositories/ffmpeg/trunk@23067 9553f0bf-9b14-0410-a0b8-cfaf0461ba5b

doc/APIchanges

@@ -12,6 +12,9 @@ libavutil:   2009-03-08
 
 API changes, most recent first:
 
+2010-05-09 - r23066 - lavfi 1.20.0 - AVFilterPicRef
+  Add interlaced and top_field_first fields to AVFilterPicRef.
+
 2010-05-01 - r23002 - lavf 52.62.0 - probe function
   Add av_probe_input_format2 to API, it allows ignoring probe
   results below given score and returns the actual probe score.