message: Add recent bugfixes to CHANGELOG.md
diff: @@ -110,7 +110,6 @@ for the list of changes made since `v2.0.0-alpha.1`.
  - `startOfWeekYear`
  ### Changed
  -- **Fixed**: fixed when parsing ISO style dates (but not valid ISO format) with a trailing Z (e.g 2012-01Z), it returns Invalid Date for FireFox/IE11 [#510](https://github.com/date-fns/date-fns/issue/510)
  - **BREAKING**: new format string API for `format` function
  which is based on [Unicode Technical Standard #35](https://www.unicode.org/reports/tr35/tr35-dates.html#Date_Field_Symbol_Table):
  @@ -579,6 +578,14 @@ for the list of changes made since `v2.0.0-alpha.1`.
  - `toDate` (previously `parse`) and `isValid` functions now accept `any` type
  as the first argument.
  +### Fixed
  +
  +- Fix the `toDate` bug occuring when parsing ISO-8601 style dates (but not valid ISO format)
  + with a trailing Z (e.g `2012-01Z`), it returned Invalid Date for FireFox/IE11 [#510](https://github.com/date-fns/date-fns/issue/510)
  +
  +- Fix `differenceIn...` functions returning negative zero in some cases:
  + [#692](https://github.com/date-fns/date-fns/issues/692)
  +
  ## [1.28.5] - 2017-05-19
  ### Fixed
  