docs(changelog): changelog for v2.10 release

Added changelog for v2.10 release.

Signed-off-by: Manish V Badarkhe <Manish.Badarkhe@arm.com>
Signed-off-by: Juan Pablo Conde <juanpablo.conde@arm.com>
Change-Id: Id06263047fcc1ec60e82f85cd09e2e4bc95830f5
8 files changed