Update .env.example

fix string interpolation issue

Author: jeremykenedy

.env.example

@@ -110,7 +110,7 @@ LARAVEL_LOGGER_FONT_AWESOME_CDN_URL=https://maxcdn.bootstrapcdn.com/font-awesome
 LARAVEL_LOGGER_BOOTSTRAP_CSS_CDN_ENABLED=false
 LARAVEL_LOGGER_BOOTSTRAP_CSS_CDN_URL=https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0/css/bootstrap.min.css
 
-LARAVEL_BLOCKER_USER_MODEL='App\Models\User'
+LARAVEL_BLOCKER_USER_MODEL=App\Models\User
 LARAVEL_BLOCKER_AUTH_ENABLED=true
 LARAVEL_BLOCKER_ROLES_ENABLED=true
 LARAVEL_BLOCKER_FLASH_MESSAGES_ENABLED=false