Use named cases for the data provider for changelog tests (#1880)

This makes it easier to identify which package has an invalid changelog
as PHPUnit displays the name of the failing case in its output (which is
easier to understand than figuring out which component has the index 23
in the data provider).

Author: stof

tests/Unit/ChangelogTest.php

@@ -172,9 +172,8 @@ public static function provideChangedlogFiles(): iterable
             ->in(\dirname(__DIR__, 2) . '/src')
             ->name('CHANGELOG.md');
 
-        /** @var \SplFileInfo $file */
         foreach ($finder as $file) {
-            yield [$file->getRealPath()];
+            yield $file->getRelativePath() => [$file->getRealPath()];
         }
     }