Update changelog

Author: rhpvorderman

CHANGELOG.rst

@@ -9,6 +9,10 @@ Changelog
 
 version 0.2.0-dev
 -----------------
++ Fixed a bug where writing of the gzip header would crash if an older version
+  of Python 3.7 was used such as on Debian or Ubuntu. This is due to
+  differences between point releases because of a backported feature. The code
+  now checks if the backported feature is present.
 + Added Python 3.9 to the testing.
 + Fixed ``setup.py`` to list setuptools as a requirement.
 + Changed homepage to reflect move to pycompression organization.