add workflow endpoint

Author: karissarjacobsen

api-reference/maestro/workflows/getWorkflowInstance.sh

@@ -0,0 +1,6 @@
+#apx-snippet-start:getWorkflowInstance
+Status=$(curl -s -w "%{http_code}\n" -i \
+    --request GET "https://api-d.docusign.com/v1/accounts/${account_id}/workflows/${workflow_id}/instances/${instance_id}" \
+    --header "Authorization: Bearer ${access_token}" \
+    --output ${response})
+#apx-snippet-end:getWorkflowInstance