Fix typo (preview instead of review)

Author: andrewheard

Firestore/CHANGELOG.md

@@ -1,6 +1,6 @@
 # 12.8.0
 - [fixed] Fix crash while fetching Auth and App Check tokens. (#15281)
-- [feature] `Pipeline` support is now available for the `Enterprise edition` as a public review feature. (#15625)
+- [feature] `Pipeline` support is now available for the `Enterprise edition` as a public preview feature. (#15625)
 - [fixed] Fixed an issue where the returned object in transaction blocks could not
   pass across actor boundaries in Swift 6 (#15467).