Update Changelog for PR for Issue 762

Author: sadielbartholomew

Changelog.rst

@@ -35,6 +35,9 @@ version 3.16.2
 * Fix bug whereby `Field.cyclic` is not updated after a
   `Field.del_construct` operation
   (https://github.com/NCAS-CMS/cf-python/issues/758)
+* Fix bug that meant `cyclic()` always returned an empty
+  set for domains produced by `cf.Field.domain`
+  (https://github.com/NCAS-CMS/cf-python/issues/762)
 
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