[Rspamd] Return CAB to archive_extensions

data/conf/rspamd/local.d/mime_types.conf

@@ -42,5 +42,6 @@ archive_extensions = {
   arj = 1,
   rar = 1,
   ace = 1,
-  7z = 1
+  7z = 1,
+  cab = 1
 };