Set environment variable to avoid Get-AzAccessToken breaking change (#1106)

* Set environment variable to avoid Get-AzAccessToken breaking change
* Update release notes

Author: AnatoliB

release_notes.md

@@ -1 +1 @@
-* Use rpcBaseUrl in Durable operations when possible
+* Set environment variable to avoid Get-AzAccessToken breaking change

src/RequestProcessor.cs

@@ -106,6 +106,11 @@ internal StreamingMessage ProcessWorkerInitRequest(StreamingMessage request)
             Environment.SetEnvironmentVariable("AZUREPS_HOST_ENVIRONMENT", $"AzureFunctions/{workerInitRequest.HostVersion}");
             Environment.SetEnvironmentVariable("POWERSHELL_DISTRIBUTION_CHANNEL", $"Azure-Functions:{workerInitRequest.HostVersion}");
 
+            // Set the environment variable to force the Get-AzAccessToken to return a
+            // plaintext token and avoid the planned breaking change.
+            // TODO: Remove this for the next PowerShell version (7.6).
+            Environment.SetEnvironmentVariable("AZUREPS_OUTPUT_PLAINTEXT_AZACCESSTOKEN", "true");
+
             StreamingMessage response = NewStreamingMessageTemplate(
                 request.RequestId,
                 StreamingMessage.ContentOneofCase.WorkerInitResponse,