docs(changelog): changelog for lts-v2.8.20 release

Change-Id: I8e1567e4febc838d38da4abaf4ce24426ec921f8
Signed-off-by: Release CI <ci@trustedfirmware.org>
diff --git a/readme.rst b/readme.rst
index 726ebfc..cdb34a3 100644
--- a/readme.rst
+++ b/readme.rst
@@ -52,3 +52,4 @@
 
 
 
+