docs(changelog): changelog for v2.7 release

Change-Id: I573e5eb3c7fad097892292c8a967dc02d72d12e6
Signed-off-by: Jayanth Dodderi Chidanand <jayanthdodderi.chidanand@arm.com>
diff --git a/package.json b/package.json
index e5cd924..0284e6f 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "trusted-firmware-a",
-  "version": "2.6.0",
+  "version": "2.7.0",
   "license": "BSD-3-Clause",
   "private": true,
   "scripts": {