Enable signing for official .NET images (#7139)

Author: lbussell

eng/pipelines/dotnet-core.yml

@@ -39,6 +39,7 @@ extends:
     stages:
     - template: /eng/docker-tools/templates/stages/dotnet/publish-config-prod.yml@self
       parameters:
+        enableSigning: true
         sourceBuildPipelineRunId: ${{ parameters.sourceBuildPipelineRunId }}
         stagesTemplate: /eng/pipelines/stages/build-test-publish-repo.yml@self
         stagesTemplateParameters:

eng/pipelines/release-staging-official.yml

@@ -50,6 +50,7 @@ extends:
     stages:
     - template: /eng/docker-tools/templates/stages/dotnet/publish-config-prod.yml@self
       parameters:
+        enableSigning: true
         sourceBuildPipelineRunId: ${{ parameters.sourceBuildPipelineRunId }}
         stagesTemplate: /eng/pipelines/stages/build-and-test.yml@self
         stagesTemplateParameters: