DOCSP-15386 Change date format in example (#147)

Author: kanchana-mongodb

source/reference/examples/path-syntax-examples.txt

@@ -246,7 +246,7 @@ The following :ref:`datalake-databases-reference` object generates a field
            "dataSources" : [
              {
                "storeName" : "accountingArchive",
-               "path" : "/invoices/{invoiceDate date}"
+               "path" : "/invoices/{invoiceDate epoch_secs}"
              }
            ]
          }