update avocado@0.6.0 in preproduction (Azure#7002)

Author: ruowan

preproduction-azure-pipelines.yml

@@ -44,6 +44,6 @@ jobs:
     displayName: 'npm install'
     inputs:
       verbose: false
-  - script: 'npm install -D @azure/avocado@0.5.1'
+  - script: 'npm install -D @azure/avocado@0.6.0'
   - script: './node_modules/.bin/avocado'
     displayName: 'Avocado'