Changelog: update

Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>

Changelog

@@ -2,6 +2,11 @@ Entries are sorted chronologically from oldest to youngest within each release,
 releases are sorted from youngest to oldest.
 
 version 4.3.1:
+ avcodec/tiff: Check input space in dng_decode_jpeg()
+ avcodec/mjpeg_parser: Adjust size rejection threshold
+ avcodec/cbs_jpeg: Fix uninitialized end index in cbs_jpeg_split_fragment()
+ avformat/sdp: Fix potential write beyond end of buffer
+ avformat/mm: Check for existence of audio stream
  avformat/mov: Fix unaligned read of uint32_t and endian-dependance in mov_read_default
  avcodec/apedec: Fix undefined integer overflow with 24bit
  avcodec/loco: Fix integer overflow with large values from loco_get_rice()