PHPUnit 10 Migration (#1302)

* Bump PHPUnit dependencies

* Set return type of base TestCase methods

From the [PHPUnit 8 release notes][1], the `TestCase` methods below now declare a `void` return type:

- `setUpBeforeClass()`
- `setUp()`
- `assertPreConditions()`
- `assertPostConditions()`
- `tearDown()`
- `tearDownAfterClass()`
- `onNotSuccessfulTest()`

[1]: https://phpunit.de/announcements/phpunit-8.html

* Ignore PHPUnit cache folder

* Adopt PHP attributes in test classes

* Declare data providers as `static`

* Add return types to test methods

* Define test classes as `final`

* Migrate phpunit.xml to phpunit 10

* Correct phpunit attribute class name

* Rename base test class

* Restructure test folders

* Fix test image paths

* Only set rules for php files in .editorconfig

* Remove php unit flag in local test env

---------

Co-authored-by: Shift <shift@laravelshift.com>

tests/Unit/Drivers/Imagick/Decoders/Base64ImageDecoderTest.php

@@ -0,0 +1,39 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Intervention\Image\Tests\Unit\Drivers\Imagick\Decoders;
+
+use PHPUnit\Framework\Attributes\CoversClass;
+use PHPUnit\Framework\Attributes\RequiresPhpExtension;
+use Intervention\Image\Drivers\Imagick\Decoders\Base64ImageDecoder;
+use Intervention\Image\Exceptions\DecoderException;
+use Intervention\Image\Image;
+use Intervention\Image\Tests\BaseTestCase;
+
+#[RequiresPhpExtension('imagick')]
+#[CoversClass(\Intervention\Image\Drivers\Imagick\Decoders\Base64ImageDecoder::class)]
+final class Base64ImageDecoderTest extends BaseTestCase
+{
+    protected Base64ImageDecoder $decoder;
+
+    protected function setUp(): void
+    {
+        $this->decoder = new Base64ImageDecoder();
+    }
+
+    public function testDecode(): void
+    {
+        $result = $this->decoder->decode(
+            base64_encode($this->getTestImageData('blue.gif'))
+        );
+
+        $this->assertInstanceOf(Image::class, $result);
+    }
+
+    public function testDecoderInvalid(): void
+    {
+        $this->expectException(DecoderException::class);
+        $this->decoder->decode('test');
+    }
+}