infra: update manifest for RD-INFRA-2021.12.21 release

The RD-INFRA-2021.12.21 release refreshes the software stack for the
Neoverse RD-Edmunds platform. So update the release tags in the manifest
file of RD-Edmunds platform.

Signed-off-by: Thomas Abraham <thomas.abraham@arm.com>
Change-Id: I12d9cd7b91e9beae8618f20fb83cfc7151a9dec2