fix typo in exception message

Author: xabbuh

src/TextUI/Configuration/Xml/Migration/Migrator.php

@@ -31,7 +31,7 @@ public function migrate(string $filename): string
         $origin = (new SchemaDetector)->detect($filename);
 
         if (!$origin->detected()) {
-            throw new Exception('The file does not validate against any know schema');
+            throw new Exception('The file does not validate against any known schema');
         }
 
         if ($origin->version() === Version::series()) {

tests/end-to-end/migration/unsupported-schema.phpt

@@ -15,7 +15,7 @@ require_once __DIR__ . '/../../bootstrap.php';
 PHPUnit %s by Sebastian Bergmann and contributors.
 
 Migration of %s failed:
-The file does not validate against any know schema
+The file does not validate against any known schema
 --CLEAN--
 <?php declare(strict_types=1);
 unlink(sys_get_temp_dir() . '/phpunit.xml');