Updates to 3rd party libraries

Add Dockerfile and specific docker-php.ini

inc/vendor/phpoffice/phpspreadsheet/tests/PhpSpreadsheetTests/Reader/XlsxTest.php

@@ -0,0 +1,19 @@
+<?php
+
+namespace PhpOffice\PhpSpreadsheetTests\Reader;
+
+use PhpOffice\PhpSpreadsheet\Reader\Xlsx;
+use PHPUnit\Framework\TestCase;
+
+class XlsxTest extends TestCase
+{
+    /**
+     * Test load Xlsx file without cell reference.
+     */
+    public function testLoadXlsxWithoutCellReference()
+    {
+        $filename = './data/Reader/XLSX/without_cell_reference.xlsx';
+        $reader = new Xlsx();
+        $reader->load($filename);
+    }
+}