Revert "Use sebastian/diff v3 for PHP 7.2+ compatibility"

This reverts commit 15994e6.

Author: swissspidy

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": "^3.0",
+        "sebastian/diff": "^4.0 || ^5.0 || ^6.0 || ^7.0",
         "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

@@ -9,6 +9,7 @@
 use Exception;
 use Mustangostang\Spyc;
 use SebastianBergmann\Diff\Differ;
+use SebastianBergmann\Diff\Output\UnifiedDiffOutputBuilder;
 
 trait Support {
 
@@ -315,7 +316,11 @@ 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 {
-		$differ = new Differ( "--- Expected\n+++ Actual\n" );
+		$builder = new UnifiedDiffOutputBuilder(
+			"--- Expected\n+++ Actual\n",
+			false
+		);
+		$differ  = new Differ( $builder );
 		return $differ->diff( $expected, $actual );
 	}
 }