[pixiv] update URL patterns (fixes #568)

Pixiv now uses new URLs for
- user profiles and illustration listings:
  - https://www.pixiv.net/en/users/<ID>
  - https://www.pixiv.net/en/users/<ID>/artworks
- bookmarks:
  - https://www.pixiv.net/en/users/<ID>/bookmarks/artworks

gallery_dl/version.py

@@ -1,9 +1,9 @@
 # -*- coding: utf-8 -*-
 
-# Copyright 2016-2019 Mike Fährmann
+# Copyright 2016-2020 Mike Fährmann
 #
 # This program is free software; you can redistribute it and/or modify
 # it under the terms of the GNU General Public License version 2 as
 # published by the Free Software Foundation.
 
-__version__ = "1.12.2"
+__version__ = "1.12.3-dev"