Add alert box for Azure DevOps in documentation that specifies the need to disable shallow fetching

Author: kimsey0

docs/input/docs/reference/build-servers/azure-devops.md

@@ -14,6 +14,14 @@ either using the Command Line build step or install an extension / custom build
 step. The custom build step requires a one-time setup to import the GitVersion
 task into your TFS or Azure DevOps Pipeline instance.
 
+:::{.alert .alert-danger}
+**Important**
+
+You must disable shallow fetch, either in the pipeline settings UI or by setting `fetchDepth: 0` in your `checkout` step;
+without it, Azure DevOps Pipelines will perform a shallow clone, which will cause GitVersion will display an error message.
+See [the Azure DevOps documentation](https://learn.microsoft.com/en-us/azure/devops/pipelines/yaml-schema/steps-checkout?view=azure-pipelines#shallow-fetch) for more information.
+:::
+
 ## Executing GitVersion
 
 ### Using GitVersion with the MSBuild Task NuGet Package