Update PHPUnit to version 9

Updated phpunit.xml using `phpunit --migrate-configuration`

composer.json

@@ -26,11 +26,11 @@
     },
     "require-dev": {
         "doctrine/dbal": "^2.5.2",
-        "phpunit/phpunit": "^8.5",
         "fzaninotto/faker": "^1.6",
         "illuminate/support": "~5.5.0 || ~5.6.0 || ~5.7.0 || ~5.8.0 || ^6.0 || ^7.0 || ^8.0",
         "mockery/mockery": "^1.3",
         "orchestra/testbench": "^3.5 || ^3.6 || ^3.7 || ^3.8 || ^4.0 || ^5.0 || ^6.0",
+        "phpunit/phpunit": "^9.3",
         "predis/predis": "^1.1"
     },
     "suggest": {

phpunit.xml

@@ -1,24 +1,16 @@
 <?xml version="1.0" encoding="UTF-8"?>
-<phpunit backupGlobals="false"
-         backupStaticAttributes="false"
-         bootstrap="./vendor/autoload.php"
-         colors="true"
-         convertErrorsToExceptions="true"
-         convertNoticesToExceptions="true"
-         convertWarningsToExceptions="true"
-         processIsolation="false"
-         stopOnFailure="false">
-    <testsuites>
-        <testsuite name="Unit">
-            <directory>./tests/Unit</directory>
-        </testsuite>
-        <testsuite name="Feature">
-            <directory>./tests/Feature</directory>
-        </testsuite>
-    </testsuites>
-    <filter>
-        <whitelist processUncoveredFilesFromWhitelist="true">
-            <directory suffix=".php">./src</directory>
-        </whitelist>
-    </filter>
-</phpunit>
+<phpunit xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" backupGlobals="false" backupStaticAttributes="false" bootstrap="./vendor/autoload.php" colors="true" convertErrorsToExceptions="true" convertNoticesToExceptions="true" convertWarningsToExceptions="true" processIsolation="false" stopOnFailure="false" xsi:noNamespaceSchemaLocation="https://schema.phpunit.de/9.3/phpunit.xsd">
+  <coverage processUncoveredFiles="true">
+    <include>
+      <directory suffix=".php">./src</directory>
+    </include>
+  </coverage>
+  <testsuites>
+    <testsuite name="Unit">
+      <directory>./tests/Unit</directory>
+    </testsuite>
+    <testsuite name="Feature">
+      <directory>./tests/Feature</directory>
+    </testsuite>
+  </testsuites>
+</phpunit>