Revert "Fix: Do not load cakephp-plugins from outside of ROOT"

This reverts merge commit b85ef39 and
commit 1597e6f.

This broke workflow for plugins based on usemuffin/skeleton.

Reported-By: robertpustulka

src/Core/Plugin.php

@@ -189,7 +189,7 @@ protected static function _loadConfig()
         $vendorFile = dirname(dirname(__DIR__)) . DIRECTORY_SEPARATOR . 'cakephp-plugins.php';
         if (!file_exists($vendorFile)) {
             $vendorFile = dirname(dirname(dirname(dirname(__DIR__)))) . DIRECTORY_SEPARATOR . 'cakephp-plugins.php';
-            if (strpos($vendorFile, ROOT) !== 0 || !file_exists($vendorFile)) {
+            if (!file_exists($vendorFile)) {
                 Configure::write(['plugins' => []]);
 
                 return;