fix(core): fix namespaces

Author: Awilum

src/core/Console/Commands/Sitemap/SitemapGenerateCommand.php

@@ -25,6 +25,7 @@
 use function Thermage\renderToString;
 use function Flextype\registry;
 use function Glowy\Filesystem\filesystem;
+use function Glowy\Strings\strings;
 
 class SitemapGenerateCommand extends Command
 {

src/core/Sitemap.php

@@ -5,7 +5,8 @@
 use function Flextype\entries;
 use function Flextype\registry;
 use function Flextype\emitter;
-use function Flextype\twig;
+use function Flextype\Plugin\Twig\twig;
+use function Glowy\Strings\strings;
 
 class Sitemap {
     public function fetch()