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/Typography/TextBlockTest.php

@@ -0,0 +1,46 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Intervention\Image\Tests\Unit\Typography;
+
+use Intervention\Image\Tests\BaseTestCase;
+use Intervention\Image\Typography\TextBlock;
+
+final class TextBlockTest extends BaseTestCase
+{
+    protected TextBlock $block;
+
+    protected function setUp(): void
+    {
+        $this->block = new TextBlock(<<<EOF
+            foo
+            FooBar
+            bar
+            EOF);
+    }
+
+    public function testCount(): void
+    {
+        $this->assertEquals(3, $this->block->count());
+    }
+
+    public function testLines(): void
+    {
+        $this->assertCount(3, $this->block->lines());
+    }
+
+    public function testGetLine(): void
+    {
+        $this->assertEquals('foo', $this->block->line(0));
+        $this->assertEquals('FooBar', $this->block->line(1));
+        $this->assertEquals('bar', $this->block->line(2));
+        $this->assertNull($this->block->line(20));
+    }
+
+    public function testLongestLine(): void
+    {
+        $result = $this->block->longestLine();
+        $this->assertEquals('FooBar', (string) $result);
+    }
+}