refactor(DateUtils.test.js): use arrow functions

Author: php-coder

src/main/frontend/src/utils/DateUtils.test.js

@@ -1,8 +1,8 @@
 import './DateUtils.js'
 
-describe('DateUtils.formatDateToDdMmYyyy()', function() {
+describe('DateUtils.formatDateToDdMmYyyy()', () => {
 
-	it('should return a string in a format dd.mm.yyyy', function() {
+	it('should return a string in a format dd.mm.yyyy', () => {
 		var date = new Date('2018-06-12T16:59:54.451Z');
 		expect(DateUtils.formatDateToDdMmYyyy(date)).toEqual('12.06.2018');
 	});