Update PHPUnit to min 9.7 to support cacheDirectory

Author: Alex Westergaard

composer.json

@@ -46,7 +46,7 @@
         "guzzlehttp/guzzle": "^7.0"
     },
     "require-dev": {
-        "phpunit/phpunit": "^9.5|^10.0"
+        "phpunit/phpunit": "^9.7|^10.0"
     },
     "minimum-stability": "stable",
     "prefer-stable": true

phpunit.xml

@@ -4,7 +4,8 @@
     beStrictAboutTestsThatDoNotTestAnything="true"
     beStrictAboutTodoAnnotatedTests="true"
     testdox="true"
-    xsi:noNamespaceSchemaLocation="https://schema.phpunit.de/10.0/phpunit.xsd">
+    xsi:noNamespaceSchemaLocation="https://schema.phpunit.de/10.0/phpunit.xsd"
+    cacheDirectory=".phpunit.cache">
     <testsuites>
         <testsuite name="Units">
             <directory>test/Unit</directory>