[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/Unit/Coordinate/FrameRateTest.php

@@ -0,0 +1,31 @@
+<?php
+
+namespace Tests\FFMpeg\Unit\Coordinate;
+
+use FFMpeg\Coordinate\FrameRate;
+use Tests\FFMpeg\Unit\TestCase;
+
+class FrameRateTest extends TestCase
+{
+    public function testGetter()
+    {
+        $fr = new FrameRate(23.997);
+        $this->assertEquals(23.997, $fr->getValue());
+    }
+
+    /**
+     * @dataProvider provideInvalidFrameRates
+     */
+    public function testInvalidFrameRate($value)
+    {
+        $this->expectException('\FFMpeg\Exception\InvalidArgumentException');
+        new FrameRate($value);
+    }
+
+    public function provideInvalidFrameRates()
+    {
+        return [
+            [0], [-1.5], [-2],
+        ];
+    }
+}