Fixed array to string conversion (#718)

* Fixed array to string conversion

Previous code would give this warning before actually showing exception message
`<warning>PHP Warning:  Array to string conversion in .../vendor/stancl/tenancy/src/CacheManager.php on line 24</warning>`

* Update variable & syntax

Co-authored-by: Samuel Štancl <samuel.stancl@gmail.com>

src/CacheManager.php

@@ -20,8 +20,10 @@ public function __call($method, $parameters)
         $tags = [config('tenancy.cache.tag_base') . tenant()->getTenantKey()];
 
         if ($method === 'tags') {
-            if (count($parameters) !== 1) {
-                throw new \Exception("Method tags() takes exactly 1 argument. {count($parameters)} passed.");
+            $count = count($parameters);
+
+            if ($count !== 1) {
+                throw new \Exception("Method tags() takes exactly 1 argument. $count passed.");
             }
 
             $names = $parameters[0];