Migrate phpunit configuration

Signed-off-by: Lukas Kämmerling <lukas.kaemmerling@hetzner-cloud.de>

Author: LKaemmerling

phpunit.xml.dist

@@ -1,30 +1,18 @@
 <?xml version="1.0" encoding="UTF-8"?>
-<phpunit backupGlobals="false"
-         backupStaticAttributes="false"
-         bootstrap="tests/bootstrap.php"
-         colors="true"
-         convertErrorsToExceptions="true"
-         convertNoticesToExceptions="true"
-         convertWarningsToExceptions="true"
-         processIsolation="false"
-         stopOnError="false"
-         stopOnFailure="false">
-
-    <testsuites>
-        <testsuite name="Unit">
-            <directory>./tests/Test/Prometheus</directory>
-        </testsuite>
-    </testsuites>
-
-    <filter>
-        <whitelist processUncoveredFilesFromWhitelist="true">
-            <directory suffix=".php">./src/Prometheus</directory>
-        </whitelist>
-    </filter>
-
-    <groups>
-        <exclude>
-            <group>Performance</group>
-        </exclude>
-    </groups>
+<phpunit xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" backupGlobals="false" backupStaticAttributes="false" bootstrap="tests/bootstrap.php" colors="true" convertErrorsToExceptions="true" convertNoticesToExceptions="true" convertWarningsToExceptions="true" processIsolation="false" stopOnError="false" stopOnFailure="false" xsi:noNamespaceSchemaLocation="https://schema.phpunit.de/9.3/phpunit.xsd">
+  <coverage processUncoveredFiles="true">
+    <include>
+      <directory suffix=".php">./src/Prometheus</directory>
+    </include>
+  </coverage>
+  <testsuites>
+    <testsuite name="Unit">
+      <directory>./tests/Test/Prometheus</directory>
+    </testsuite>
+  </testsuites>
+  <groups>
+    <exclude>
+      <group>Performance</group>
+    </exclude>
+  </groups>
 </phpunit>