Bump to PHPStan Latte level 6

Oh look this was easy.

Ref #141

Author: spaze

site/phpstan-latte-templates.neon

@@ -2,7 +2,7 @@ parameters:
 	tmpDir: /tmp/phpstan/michalspacek.cz-latte-templates
 	paths:
 		- app
-	level: 5
+	level: 6
 	latte:
 		engineBootstrap: app/PhpStan/latteEngine.php
 		presenterFactoryBootstrap: app/PhpStan/presenterFactory.php