updated date and added security note

Author: TomJaeger

docs/installation/changelog.md

@@ -9,7 +9,9 @@
 # ExpressionEngine v6 Change Log
 
 ## Version 6.4.16
-(Release: January 16, 2024)
+(Release: January 18, 2024)
+
+NOTE: **Important:** This version includes important security updates.
 
 - **Contributors** 🙌
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