Update Obtain credentials using TokenLibrary.ipynb

Author: nirav2

Notebooks/Spark.NET C#/Obtain credentials using TokenLibrary.ipynb

@@ -19,9 +19,9 @@
         "// Example connection string (for storage): \"DefaultEndpointsProtocol=https;AccountName=<accountname>;AccountKey=<accountkey>\"\n",
         "\n",
         "using Microsoft.Spark.Extensions.Azure.Synapse.Analytics.Utils;\n",
-        "string connectionString = TokenLibrary.getConnectionString(\"<linkedServiceName>\");"
+        "string connectionString = TokenLibrary.GetConnectionString(\"<linkedServiceName>\");"
       ],
       "attachments": {}
     }
   ]
-}
+}