FirebaseAuth changelog update for 10.4.0 (#10663)

Author: paulb777

FirebaseAuth/CHANGELOG.md

@@ -1,3 +1,7 @@
+# 10.4.0
+- [fixed] Fix secure coding bugs in MFA. (#10632)
+- [fixed] Added handling of error returned from a blocking cloud function. (#10628)
+
 # 10.2.0
 - [fixed] Fix a bug where the linking/reauth flows errors are not caught. (#10267)
 - [fixed] Force to recaptcha verification flow for phone auth in simulators. (#10426)