Require constructor property promotion

PHP 8.0+ feature so code targeting older PHPs would need to exclude it, just like trailing commas in calls for example

Author: spaze

src/ruleset.xml

@@ -67,6 +67,7 @@
 			<property name="maxLinesCountBeforeWithoutComment" value="1"/>
 		</properties>
 	</rule>
+	<rule ref="SlevomatCodingStandard.Classes.RequireConstructorPropertyPromotion"/>
 	<rule ref="SlevomatCodingStandard.Classes.TraitUseDeclaration"/>
 	<rule ref="SlevomatCodingStandard.Classes.TraitUseSpacing">
 		<properties>