Upgrade phpunit config

phpunit.xml.dist

-<phpunit backupGlobals="false"
-         backupStaticAttributes="false"
-         cacheResult ="false"
-         colors="true"
-         convertErrorsToExceptions="true"
-         convertNoticesToExceptions="true"
-         convertWarningsToExceptions="true"
-         processIsolation="false"
-         stopOnFailure="false"
-         bootstrap="tests/bootstrap.php"
->
+<?xml version="1.0"?>
+<phpunit xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" backupGlobals="false" backupStaticAttributes="false" cacheResult="false" colors="true" convertErrorsToExceptions="true" convertNoticesToExceptions="true" convertWarningsToExceptions="true" processIsolation="false" stopOnFailure="false" bootstrap="tests/bootstrap.php" xsi:noNamespaceSchemaLocation="https://schema.phpunit.de/9.3/phpunit.xsd">
+  <coverage>
+    <include>
+      <directory suffix=".php">./src</directory>
+    </include>
+  </coverage>
   <testsuites>
     <testsuite name="Coworker Test Suite">
       <directory>./tests/</directory>
     </testsuite>
   </testsuites>
-
-  <filter>
-    <whitelist>
-      <directory suffix=".php">./src</directory>
-    </whitelist>
-  </filter>
 </phpunit>