Fixes #10

* upgrade phpunit configuration file

Author: Xavier Marchegay

phpunit.xml.dist

@@ -1,27 +1,27 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <phpunit xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-         xsi:noNamespaceSchemaLocation="https://schema.phpunit.de/9.6/phpunit.xsd"
+         xsi:noNamespaceSchemaLocation="https://schema.phpunit.de/12.0/phpunit.xsd"
          bootstrap="vendor/autoload.php"
-         cacheResultFile=".phpunit.cache/test-results"
+         cacheDirectory=".phpunit.cache"
          executionOrder="depends,defects"
-         forceCoversAnnotation="true"
-         beStrictAboutCoversAnnotation="true"
+         requireCoverageMetadata="true"
+         beStrictAboutCoverageMetadata="true"
          beStrictAboutOutputDuringTests="true"
-         beStrictAboutTodoAnnotatedTests="true"
-         convertDeprecationsToExceptions="true"
          failOnRisky="true"
-         failOnWarning="true"
-         verbose="true">
+         failOnWarning="true">
+
     <testsuites>
         <testsuite name="default">
             <directory>tests</directory>
         </testsuite>
     </testsuites>
 
-    <coverage cacheDirectory=".phpunit.cache/code-coverage"
-              processUncoveredFiles="true">
+    <source>
         <include>
             <directory suffix=".php">src</directory>
         </include>
+    </source>
+
+    <coverage>
     </coverage>
-</phpunit>
+</phpunit>