Use Env::get instead of env (#745)

It conflicts with other `env()` global functions (such as CakePHP), and most of them don't handle closures.

src/Mcamara/LaravelLocalization/LaravelLocalization.php

@@ -5,6 +5,7 @@
 use Illuminate\Config\Repository;
 use Illuminate\Contracts\Routing\UrlRoutable;
 use Illuminate\Support\Str;
+use Illuminate\Support\Env;
 use Mcamara\LaravelLocalization\Exceptions\SupportedLocalesNotDefined;
 use Mcamara\LaravelLocalization\Exceptions\UnsupportedLocaleException;
 
@@ -1036,7 +1037,7 @@ protected function normalizeAttributes($attributes)
      */
     protected function getForcedLocale()
     {
-        return env(static::ENV_ROUTE_KEY, function () {
+        return Env::get(static::ENV_ROUTE_KEY, function () {
             $value = getenv(static::ENV_ROUTE_KEY);
 
             if ($value !== false) {