Add readdirp version

Resolves https://github.com/MicrosoftDocs/azure-docs/issues/42899

Author: anthonychu

articles/azure-functions/durable/durable-functions-cloud-backup.md

@@ -89,7 +89,7 @@ And here is the implementation:
 
 [!code-javascript[Main](~/samples-durable-functions/samples/javascript/E2_GetFileList/index.js)]
 
-The function uses the `readdirp` module to recursively read the directory structure.
+The function uses the `readdirp` module (version 2.x) to recursively read the directory structure.
 
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