Update image name for Mariner 1.0

[mthalman]

The CBL-Mariner 1.0 Helix Dockerfile is referencing an obsolete image name that no longer works.

It leads to this build failure:

PULLING LATEST BASE IMAGES
--------------------------
-- EXECUTING: docker pull --platform linux/amd64 cblmariner.azurecr.io/base/core:1.0
Error response from daemon: Head "[https://cblmariner.azurecr.io/v2/base/core/manifests/1.0"](https://cblmariner.azurecr.io/v2/base/core/manifests/1.0%22): unauthorized: authentication required, visit https://aka.ms/acr/authorization for more information.

The image name should be changed to mcr.microsoft.com/cbl-mariner/base/core:1.0 instead.

This is blocking the build of #832.

[sbomer]

I'm trying your suggested fix as part of #832.