Abstract factory (#366)

* rewrite of the Abstract Factory pattern

* update composer deps

* fixed argument to json_encode which cannot be null

Creational/AbstractFactory/WinCsvWriter.php

@@ -0,0 +1,11 @@
+<?php
+
+namespace DesignPatterns\Creational\AbstractFactory;
+
+class WinCsvWriter implements CsvWriter
+{
+    public function write(array $line): string
+    {
+        return join(',', $line) . "\r\n";
+    }
+}