DOC: Add skipped PR to changelog

Author: effigies

Changelog

@@ -32,6 +32,8 @@ New feature release in the 4.0.x series.
 
 New features
 ------------
+* ``nib-convert`` CLI tool to make image type and data dtype conversion accessible
+  via the command line. (pr/1113) (CM, reviewed by Ariel Rokem)
 * Add ``'mask'``, ``'compat'`` and ``'smallest'`` dtype aliases to NIfTI images
   to allow for dtype specifications that can depend on the contents of the data.
   ``'mask'`` is a synonym for ``uint8``. ``'compat'`` will find the nearest