Tag_Docs job - An image label with the label Ubuntu16 does not exist. (…

…#110)

* Tag_Docs job - An image label with the label Ubuntu16 does not exist.

issue:

Pipelines - Run 20240426.1 logs (azure.com)

##[warning]An image label with the label Ubuntu16 does not exist. 
,##[error]The remote provider was unable to process the request. 
Pool: Azure Pipelines 

Attempt to fix by specifying which image to use.

* wip: address PR comments - simplify vmImage specification

azure-pipelines.yml

@@ -197,10 +197,12 @@ stages:
   jobs:
    - job: Tag_Docs
      displayName: Tag Docs
+     pool:
+       vmImage: 'ubuntu-latest'
      steps:
      - task: tagBuildOrRelease@0
        displayName: Tag Docs
        inputs:
         type: "Build"
         tags: "hasDocs"
-        condition: and(contains(variables['Build.SourceVersionMessage'], '[publish docs]'), not(contains(variables['Build.SourceVersionMessage'], '(dev)')))
+        condition: and(contains(variables['Build.SourceVersionMessage'], '[publish docs]'), not(contains(variables['Build.SourceVersionMessage'], '(dev)')))