update ChangeLog
update ChangeLog

Change-Id: I12c2b718e99087201a57f7ab7cc4c16374e205f6

webmproject/libwebp,webmproject/libwebp,PKRoma/libwebp,PKRoma/libwebp,PKRoma/libwebp,webmproject/libwebp,PKRoma/libwebp,PKRoma/libwebp,PKRoma/libwebp,webmproject/libwebp,webmproject/libwebp