docs(changelog): changelog for lts-v2.8.16 release

Generated with the command:
npm run release -- --release-as 2.8.16

Signed-off-by: Yann Gautier <yann.gautier@st.com>
Change-Id: I6d4f76377b89b87d93f847c75784b774ba5853a1
diff --git a/docs/conf.py b/docs/conf.py
index c253f90..6a89e22 100644
--- a/docs/conf.py
+++ b/docs/conf.py
@@ -14,8 +14,8 @@
 
 project = "Trusted Firmware-A"
 author = "Trusted Firmware-A contributors"
-version = "2.8.15"
-release = "2.8.15"
+version = "2.8.16"
+release = "2.8.16"
 
 # -- General configuration ---------------------------------------------------