test: ✅ Update phpunit config file format.

.gitignore

@@ -5,3 +5,4 @@ phpunit.phar
 composer.lock
 .phpunit.result.cache
 .idea
+.phpunit*

phpunit.xml

@@ -1,25 +1,19 @@
 <?xml version="1.0" encoding="UTF-8"?>
-<phpunit backupGlobals="false"
-    backupStaticAttributes="false"
-    bootstrap="vendor/autoload.php"
-    colors="true"
-    convertErrorsToExceptions="true"
-    convertNoticesToExceptions="true"
-    convertWarningsToExceptions="true"
-    processIsolation="false"
-    stopOnFailure="true"
->
-    <testsuites>
-        <testsuite name="Test Suite">
-            <directory>tests</directory>
-        </testsuite>
-    </testsuites>
-    <filter>
-        <whitelist processUncoveredFilesFromWhitelist="true">
-            <directory suffix=".php">./src</directory>
-        </whitelist>
-    </filter>
-    <logging>
-        <log type="coverage-clover" target="build/logs/clover.xml"/>
-    </logging>
+<phpunit xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" backupGlobals="false" bootstrap="vendor/autoload.php" colors="true" processIsolation="false" stopOnFailure="true" xsi:noNamespaceSchemaLocation="https://schema.phpunit.de/11.2/phpunit.xsd" cacheDirectory=".phpunit.cache" backupStaticProperties="false">
+  <coverage>
+    <report>
+      <clover outputFile="build/logs/clover.xml"/>
+    </report>
+  </coverage>
+  <testsuites>
+    <testsuite name="Test Suite">
+      <directory>tests</directory>
+    </testsuite>
+  </testsuites>
+  <logging/>
+  <source>
+    <include>
+      <directory suffix=".php">./src</directory>
+    </include>
+  </source>
 </phpunit>