docs: update changelog

Changelog

=========

0.6.1 (Pending)

1.0.0 (Pending)

--------------

- Report TRAN_AGS in error report. This allows the reader to verify whether the

  validation was performed using correct dictionary (Issue #112)

- Report SHA256 hash of file in error report. This provides a traceable link

  between the error report and the AGS4 file from which it was generated.

  (Issue #112)

- Fix bug that could cause a crash when exporting error log to JSON. (Issue #113)

- Add new category of error named "Validator Process Error". This indicates that

  the validation terminated prematurely and should be re-run after fixing

  current errors. (Issue #114)

- Fix crash in Python 3.12.4 trying to change which character set to use

  reading a file/stream that does not support the reconfigure() method.

  Typical error message `'_io.StringIO' object has no attribute 'reconfigure'`

  (Issue #116)

- Change message about invalid TRAN_AGS entries from warning to FYI.

- Change message about ABBR_DESC entries not matching those in the standard

  dictionary from warning to FYI.