Pagination does not preserve filter by tag

[jkufner]

Start the demo and go to http://localhost:8000/en/blog/?tag=consectetur, then click "Next →" button in the paginator.

The next URL should be http://localhost:8000/en/blog/page/2?tag=consectetur, but it is http://localhost:8000/en/blog/page/2 instead — the ?tag=consectetur is missing.

[javiereguiluz]

Thanks for reporting ... and fixing this in #1136.