Use sebastian/diff v3 for PHP 7.2+ compatibility

Co-authored-by: swissspidy <[email protected]>

Author: Copilot

composer.json

@@ -20,7 +20,7 @@
         "phpstan/phpstan-deprecation-rules": "^1.2 || ^2.0",
         "phpstan/phpstan-phpunit": "^1.4 || ^2.0",
         "phpstan/phpstan-strict-rules": "^1.6 || ^2.0",
-        "sebastian/diff": "^4.0 || ^5.0 || ^6.0 || ^7.0",
+        "sebastian/diff": "^3.0",
         "swissspidy/phpstan-no-private": "^0.2.1 || ^1.0",
         "szepeviktor/phpstan-wordpress": "^v1.3.5",
         "wp-cli/config-command": "^1 || ^2",

src/Context/Support.php

@@ -9,7 +9,6 @@
 use Exception;
 use Mustangostang\Spyc;
 use SebastianBergmann\Diff\Differ;
-use SebastianBergmann\Diff\Output\UnifiedDiffOutputBuilder;
 
 trait Support {
 
@@ -316,11 +315,7 @@ protected function check_that_yaml_string_contains_yaml_string( $actual_yaml, $e
 	 * @return string The unified diff output.
 	 */
 	protected function generate_diff( string $expected, string $actual ): string {
-		$builder = new UnifiedDiffOutputBuilder(
-			"--- Expected\n+++ Actual\n",
-			false
-		);
-		$differ  = new Differ( $builder );
+		$differ = new Differ( "--- Expected\n+++ Actual\n" );
 		return $differ->diff( $expected, $actual );
 	}
 }