Update the GetDatasetMetadata API docs to include owner_username.

Author: hemang1729

docs/explorer/Explorer_API/Dataset_Metadata/get_dataset_metadata_api.md

@@ -14,10 +14,14 @@ The GetDatasetMetadata API allows you to get the metadata associated with a data
 
 The `get_dataset_metadata method` is used to get the metadata for a dataset from the Invariant API using the `dataset_name`.
 
-##### `request` <span class='type'>dataset_name</span> <span class='required'/>
+##### `dataset_name` <span class='type'>str</span> <span class='required'/>
 
 The name of the dataset.
 
+##### `owner_username` <span class='type'>str</span> <span class='optional'/>
+
+The name of the owner of the dataset. If the dataset is not owned by the caller and it is public, pass in the owner_username with the dataset_name to view it metadata.
+
 ##### `request_kwargs` <span class='type'>Optional[Dict[str, Any]]</span> <span class='optional'/>
 
 Additional keyword arguments to pass to the requests method. Default is `None`.