change exports to default to retain compatibility with existing imports

Signed-off-by: Michael Telatynski <7t3chguy@gmail.com>

src/components/views/messages/DateSeparator.js

@@ -32,7 +32,7 @@ function getdaysArray() {
     ];
 }
 
-export class DateSeparator extends React.Component {
+export default class DateSeparator extends React.Component {
     static propTypes = {
         ts: PropTypes.number.isRequired,
     };

src/components/views/messages/MessageTimestamp.js

@@ -19,7 +19,7 @@ import React from 'react';
 import PropTypes from 'prop-types';
 import {formatFullDate, formatTime} from 'matrix-react-sdk/lib/DateUtils';
 
-export class MessageTimestamp extends React.Component {
+export default class MessageTimestamp extends React.Component {
     static propTypes = {
         ts: PropTypes.number.isRequired,
         showTwelveHour: PropTypes.bool,