Bump to macos-12 build image (#1031)

AzDO will remove macos-11 in about two weeks.

Author: akoeplinger

.azure/templates/jobs/default-build.yml

@@ -75,7 +75,7 @@ jobs:
       name: ${{ parameters.poolName }}
     ${{ if and(eq(parameters.poolName, ''), eq(parameters.agentOs, 'macOS')) }}:
       name: Azure Pipelines
-      image: macOS-11
+      image: macOS-12
       os: macOS
     ${{ if and(eq(parameters.poolName, ''), eq(parameters.agentOs, 'Linux')) }}:
       image: 1es-ubuntu-2004