Update PHPUnit configuration

Author: jessarcher

.gitignore

@@ -1,5 +1,5 @@
 .env
-.phpunit.result.cache
+/.phpunit.cache
 composer.lock
 phpunit.xml
 /vendor

phpunit.xml.dist

@@ -1,23 +1,21 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <phpunit bootstrap="vendor/autoload.php"
+         cacheDirectory=".phpunit.cache"
          backupGlobals="false"
-         backupStaticAttributes="false"
+         backupStaticProperties="false"
          colors="true"
-         verbose="true"
-         convertErrorsToExceptions="true"
-         convertNoticesToExceptions="true"
-         convertWarningsToExceptions="true"
+         failOnNotice="true"
+         failOnWarning="true"
          processIsolation="false"
          stopOnFailure="false">
     <testsuites>
         <testsuite name="Test Suite">
             <directory>tests</directory>
         </testsuite>
     </testsuites>
-    <filter>
-        <whitelist>
+    <source>
+        <include>
             <directory suffix=".php">src/</directory>
-        </whitelist>
-    </filter>
+        </include>
+    </source>
 </phpunit>
-