Django-wkhtmltopdf

-------
* Fix for Django 4.0
* Remove travis CI
* Add GitHub actions CI with for Python 3.7, 3.8 3.9 and Django 2.2, 3.2 and 4.0

--------

* Fix `AttributeError` exception handling to only catch specific `AttributeError`.
* Fix list `NO_ARGUMENT_OPTIONS`.
* Add Django 3 support.
* Add Python 3.6, 3.7 and Django 2 to travis test matrix.
* Fix `make_absolute_paths` regular expression failure.

-----

* Adding support for cover page
* fix templates without context_processor
* Update installation docs
* Allow rendering PDFs when request is None
* Fix argument passing

-----

* Remove kwarg `current_app=None`.
* Fix download information badget on `README.rst`.
* Refactor to better support multiple pages.
* Remove dependency on Django template engine.
* Fix unidecode bytes error on python2.

-----

This release is identical to `2.1.0`, but with a major version bump to reflect the backwards-incompatible changes.

-----

This release is backwards-incompatible. Using `3.0.0` is recommended to indicate this.

* Move logic from views to `utils` to make it more usable. **backwards incompatible**
- Adds `convert_to_pdf`, `render_pdf_from_template` and `render_to_temporary_file` to `utils`.
- Removes `render_to_temporary_file` and `convert_to_pdf` from `views.PDFResponse` - thanks johnraz.
* Enable tests for Django >= 1.7 - thanks timb07
* Fix to accomodate changes to mod_wsgi v.4.4.14 - thanks powderflask
* Fix bytes string conversion issue - thanks danielgatis