[BC] Upgraded dependencies, dropped support for anything below PHP 8.0. (#849)

* GitHub actions + style fixes + updated packages

* Fixed workflows dir

* Support for PHP 8.1 (#1)

* Update README.md

* Revert some changes from upstream

tests/FFMpeg/Functional/FunctionalTestCase.php

@@ -0,0 +1,19 @@
+<?php
+
+namespace Tests\FFMpeg\Functional;
+
+use FFMpeg\FFMpeg;
+use Tests\FFMpeg\BaseTestCase;
+
+abstract class FunctionalTestCase extends BaseTestCase
+{
+    /**
+     * @param array $configuration
+     *
+     * @return FFMpeg
+     */
+    public function getFFMpeg($configuration = [])
+    {
+        return FFMpeg::create(array_merge(['timeout' => 300], $configuration));
+    }
+}