Update CHANGELOGs for 8.10.0 (#8979)

FirebasePerformance/CHANGELOG.md

@@ -1,4 +1,4 @@
-# Unreleased
+# Version 8.10.0
 * Fix a crash related to FPRSessionDetails. (#8691)
 * Fix heap-buffer overflow when encoding sessions. (#8849)
 

FirebaseRemoteConfig/CHANGELOG.md

@@ -1,4 +1,4 @@
-# Unreleased
+# v8.10.0
 - [fixed] Fixed cached config not loading if device is locked. (#8807)
 
 # v8.0.0