Update devops-build-tool-tasks.md

Add parameter "MaxAsyncWaitTime" which is missing from documentation under Copy Environment task

power-platform/alm/devops-build-tool-tasks.md

@@ -721,6 +721,7 @@ steps:
 | `OverrideFriendlyName`<br/>Override friendly name | Change the target environment's friendly name to another name (true\|false). |
 | `FriendlyName`<br/>Friendly name | The friendly name of the target environment. |
 | `DisableAdminMode`<br/>Disable admin mode | Whether to disable administration mode (true\|false). |
+| `MaxAsyncWaitTime`<br/>Maximum wait time | Maximum wait time in minutes for the asynchronous operation; default is 60 min (1 hr), same as Azure DevOps default for tasks. |
 
 ### Power Platform Restore Environment