ChangeLog: Set release date

Signed-off-by: Minos Galanakis <minos.galanakis@arm.com>
diff --git a/ChangeLog b/ChangeLog
index 2989ba3..27b5820 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,6 +1,6 @@
 Mbed TLS ChangeLog (Sorted per branch, date)
 
-= Mbed TLS x.x.x branch released xxxx-xx-xx
+= Mbed TLS 2.28.5 branch released 2023-10-05
 
 Features
    * The documentation of mbedtls_ecp_group now describes the optimized