Update Changelog.rst

Co-authored-by: Sadie L. Bartholomew <[email protected]>

Author: davidhassell

Changelog.rst

@@ -7,8 +7,6 @@ version NEXTVERSION
   (https://github.com/NCAS-CMS/cf-python/issues/784)
 * Include the UM version as a field property when reading UM files
   (https://github.com/NCAS-CMS/cf-python/issues/777)
-* Include the UM version as a field property when reading UM files
-  (https://github.com/NCAS-CMS/cf-python/issues/777)
 * Fix bug where `cf.example_fields` returned a `list` of Fields rather
   than a `Fieldlist`
   (https://github.com/NCAS-CMS/cf-python/issues/725)