fix(provider): Fix variable type mismatch (#10)

Author: Log1x

src/SageSvgServiceProvider.php

@@ -77,7 +77,7 @@ protected function customDirectives()
             return;
         }
 
-        if ($directives = collect($this->app->config->get('svg.directives'))->isEmpty()) {
+        if (($directives = collect($this->app->config->get('svg.directives')))->isEmpty()) {
             return;
         }