Add test-case for urns in a xs:Name value

Author: tvdijen

tests/XML/Assert/NameTest.php

@@ -42,6 +42,7 @@ public static function provideValidName(): array
         return [
             'valid' => [true, 'Snoopy'],
             'diacritical' => [true, 'fööbár'],
+            'urn' => [true, 'urn:myAttributeName'],
             'start with colon' => [true, ':CMS'],
             'start with dash' => [true, '-1950-10-04'],
         ];