update vg doc
@@ -9,6 +9,8 @@ description: |-
Use this data source to access information about existing Variable Groups within Azure DevOps.
+~> **Note:** Secret values are masked by service and cannot be obtained through API. [Set secret variables](https://docs.microsoft.com/en-us/azure/devops/pipelines/process/variables?view=azure-devops&tabs=yaml%2Cbatch#secret-variables)
+
## Example Usage
```hcl
