Update variable group in Test stage for clarity on AzureSP usage (#506)

* Update variable group in Test stage to specify CosmosDB.AzureSP.MCAPS

* Clarify comments for variable group in Test stage to specify CosmosDB Azure Service Principal (MCAPS environment)

* Fix formatting in README.md note and update azure-pipelines.yml to include README.md and CHANGELOG.md in triggers

Author: PlagueHO

README.md

@@ -396,7 +396,8 @@ account in Azure:
 
 > [!NOTE]
 > This function is not currently working due to an issue in the Microsoft/DocumentDB
-> Provider. See [this issue](https://github.com/Azure/azure-powershell/issues/3650) for more information.
+> Provider. See [this issue](https://github.com/Azure/azure-powershell/issues/3650)
+> for more information.
 
 ```powershell
 Get-CosmosDbAccountConnectionString -Name MyAzureCosmosDB -ResourceGroupName MyCosmosDbResourceGroup

azure-pipelines.yml

@@ -9,6 +9,8 @@ trigger:
     - tests/*
     - docs/*
     - RequiredModules.psd1
+    - README.md
+    - CHANGELOG.md
   tags:
     include:
     - "v*"
@@ -61,7 +63,8 @@ stages:
   - stage: Test
     dependsOn: Build
     variables:
-      - group: CosmosDB.AzureSP
+      - group: CosmosDB.AzureSP.MCAPS # Variable group for CosmosDB Azure Service Principal (MCAPS environment)
+      # - group: CosmosDB.AzureSP.MSDN # Variable group for CosmosDB Azure Service Principal (MSDN environment)
     jobs:
       # Unit Test Matrix
       - job: Unit_Test_Matrix