add postgresql and custom downloader

src/SPC/store/source/PostgreSQLSource.php

@@ -0,0 +1,29 @@
+<?php
+
+declare(strict_types=1);
+
+namespace SPC\store\source;
+
+use SPC\store\Downloader;
+
+class PostgreSQLSource extends CustomSourceBase
+{
+    public const NAME = 'postgresql';
+
+    public function fetch()
+    {
+        Downloader::fetchSource('postgresql', self::getLatestInfo());
+    }
+
+    public function getLatestInfo(): array
+    {
+        [$url, $filename, $version] = Downloader::getFromFileList('postgresql', [
+            'url' => 'https://www.postgresql.org/ftp/source/',
+            'regex' => '/href="(?<file>v(?<version>[^"]+)\/)"/',
+        ]);
+        return [
+            'type' => 'url',
+            'url' => "https://ftp.postgresql.org/pub/source/{$filename}postgresql-{$version}.tar.gz",
+        ];
+    }
+}