mention changes in news

Author: dajmcdon

NEWS.md

@@ -11,6 +11,8 @@ Pre-1.0.0 numbering scheme: 0.x will indicate releases, while 0.0.x will indicat
   `data(<dataset name>)`, but can be accessed with 
   `data(<dataset name>, package = "epidatasets")`, `epidatasets::<dataset name>` 
   or, after loading the package, the name of the dataset alone (#382).
+- Addresses upstream breaking changes from cmu-delphi/epiprocess#595 (`growth_rate()`). 
+  Corresponding arguments in `step_growth_rate()` have been removed.
 
 ## Improvements