Reverted back php-unit version

Author: skipperbent

.phpunit.result.cache

@@ -31,7 +31,7 @@
     "ext-json": "*"
   },
   "require-dev": {
-    "phpunit/phpunit": "^9.0",
+    "phpunit/phpunit": "^6.0",
     "mockery/mockery": "^1"
   },
   "autoload": {

composer.json

@@ -9,10 +9,16 @@
         convertNoticesToExceptions="true"
         convertWarningsToExceptions="true"
         processIsolation="false"
-        stopOnFailure="false">
+        stopOnFailure="false"
+        syntaxCheck="false">
     <testsuites>
         <testsuite name="SimpleRouter Test Suite">
             <directory>tests/Pecee/SimpleRouter/</directory>
         </testsuite>
     </testsuites>
+    <filter>
+        <whitelist processUncoveredFilesFromWhitelist="true">
+            <directory suffix=".php">src</directory>
+        </whitelist>
+    </filter>
 </phpunit>