updated whats new for release (#413)

Author: kthyng

doc/whats-new.rst

@@ -3,10 +3,11 @@
 What's New
 ----------
 
-v0.7.8 (unreleased)
-===================
+v0.7.8 (Jan 31, 2023)
+=====================
 
-- Optionally use the `regex` package to continue supporting global flags in regular expressions that are not at start of pattern. (:pr:`408`). By `Kristen Thyng`_
+- Optionally use the `regex` package to continue supporting global flags in regular expressions that are not at start of pattern (:pr:`408`). By `Kristen Thyng`_
+- Added link to docs for a new example "COSIMA ocean-sea ice model demo" (:pr:`397`). By `Aidan Heerdegen`_
 
 v0.7.7 (Jan 14, 2023)
 =====================
@@ -205,4 +206,5 @@ v0.1.3
 .. _`Luke Davis`: https://github.com/lukelbd
 .. _`Martin Schupfner`: https://github.com/sol1105
 .. _`Mathias Hauser`: https://github.com/mathause
+.. _`Aidan Heerdegen`: https://github.com/aidanheerdegen
 .. _`flag variables`: http://cfconventions.org/Data/cf-conventions/cf-conventions-1.8/cf-conventions.html#flags