Update phpunit.

Signed-off-by: Mior Muhammad Zaki <crynobone@gmail.com>

phpunit.xml

@@ -1,27 +1,26 @@
 <?xml version="1.0" encoding="UTF-8"?>
-<phpunit backupGlobals="false"
-     backupStaticAttributes="false"
-     beStrictAboutTestsThatDoNotTestAnything="false"
-     bootstrap="vendor/autoload.php"
-     cacheResult="false"
-     colors="true"
-     convertErrorsToExceptions="true"
-     convertNoticesToExceptions="true"
-     convertWarningsToExceptions="true"
-     processIsolation="false"
-     stopOnFailure="false"
-     verbose="true"
->
-
-    <testsuites>
-        <testsuite name="Orchestra\Support Test Suite">
-            <directory suffix="Test.php">./tests/</directory>
-        </testsuite>
-    </testsuites>
-
-    <filter>
-        <whitelist addUncoveredFilesFromWhitelist="false">
-            <directory suffix=".php">src/</directory>
-        </whitelist>
-    </filter>
+<phpunit xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:noNamespaceSchemaLocation="https://schema.phpunit.de/9.3/phpunit.xsd"
+         backupGlobals="false"
+         backupStaticAttributes="false"
+         beStrictAboutTestsThatDoNotTestAnything="false"
+         bootstrap="vendor/autoload.php"
+         cacheResult="false"
+         colors="true"
+         convertErrorsToExceptions="true"
+         convertNoticesToExceptions="true"
+         convertWarningsToExceptions="true"
+         processIsolation="false"
+         stopOnFailure="false"
+         verbose="true">
+  <coverage includeUncoveredFiles="false">
+    <include>
+      <directory suffix=".php">src/</directory>
+    </include>
+  </coverage>
+  <testsuites>
+    <testsuite name="Orchestra\Support Test Suite">
+      <directory suffix="Test.php">./tests/</directory>
+    </testsuite>
+  </testsuites>
 </phpunit>