cnf-reference-arch: utilize release branch instead of tag

The 2022.12.30 release of CRA had hotfixes added. A branch has been
created for the release to include these hotfixes, so the manifest file
should be updated to utilize the release branch, in place of the tag.

Signed-off-by: Nathan Brown <nathan.brown@arm.com>
Reviewed-by: Dhruv Tripathi <dhruv.tripathi@arm.com>

Change-Id: I5634839b8be3a82dc0fd406987f5c72985bd9e4a