Migrate PHPUnit configuration (#1010)

phpunit.xml.dist

@@ -1,5 +1,7 @@
 <?xml version="1.0" encoding="UTF-8"?>
-<phpunit bootstrap="vendor/autoload.php"
+<phpunit xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:noNamespaceSchemaLocation="https://schema.phpunit.de/9.3/phpunit.xsd"
+         bootstrap="vendor/autoload.php"
          backupGlobals="false"
          backupStaticAttributes="false"
          colors="true"
@@ -14,9 +16,9 @@
             <directory>tests</directory>
         </testsuite>
     </testsuites>
-    <filter>
-        <whitelist>
+    <coverage>
+        <include>
             <directory suffix=".php">src/</directory>
-        </whitelist>
-    </filter>
+        </include>
+    </coverage>
 </phpunit>