changelog: update release version and doc links

The Q2 release version will be v22.06.
The unnecessary links to document files are removed.

Signed-off-by: Lijian Zhang <Lijian.Zhang@arm.com>
Reviewed-by: Tianyu Li <tianyu.li@arm.com>
Reviewed-by: Honnappa Nagarahalli <honnappa.nagarahalli@arm.com>

Change-Id: I337c4941095f861fe7d2fe9c7556dfbae229f19e