PHPCompatibilitySymfonyPolyfillPHP80: update ruleset for PHPCompatibility 10.0-alpha1

As of PHPCompatibility 10.0.0, we detect and handle the use of PHP 8.0 attributes (though I expect _how_ to still change a little more).
In this case, an attribute is applied to the polyfill for the `Attribute` class, so we need to ignore that attribute ;-)

Author: jrfnl

PHPCompatibilitySymfonyPolyfillPHP80/ruleset.xml

@@ -22,4 +22,9 @@
         <exclude name="PHPCompatibility.Classes.NewClasses.valueerrorFound"/>
     </rule>
 
+    <!-- Prevent false positives being thrown when run over the code of polyfill-util itself. -->
+    <rule ref="PHPCompatibility.Attributes.NewAttributes.PHPNativeAttributeFound">
+        <exclude-pattern>/polyfill-php80/Resources/stubs/Attribute\.php$</exclude-pattern>
+    </rule>
+
 </ruleset>