ci: use phpunit 9 coverage syntax

Author: g105b

phpunit.xml

@@ -1,7 +1,7 @@
 <?xml version="1.0"?>
 <phpunit
 	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-	xsi:noNamespaceSchemaLocation="https://schema.phpunit.de/10.1/phpunit.xsd"
+	xsi:noNamespaceSchemaLocation="https://schema.phpunit.de/9.5/phpunit.xsd"
 	colors="true"
 	cacheDirectory="test/phpunit/.phpunit.cache"
 	bootstrap="vendor/autoload.php"
@@ -18,11 +18,10 @@
 
 	<logging />
 
-	<source>
+	<coverage>
 		<include>
-			<directory>
-				src/
-			</directory>
+			<directory suffix=".php">src</directory>
 		</include>
-	</source>
+	</coverage>
+
 </phpunit>