Django-linkcheck

* Added support for Django 3.2 and 4.0 and removed support for Django < 2.2.
* Ignore raw `pre_save` signal (Timo Ludwig, 106).

* The 1.8 release contained unwanted temporary stuff and was
therefore a broken release. Many thanks to Stefan Borer for
noticing that.

* Added explicit `listeners.register_listeners` and
`listeners.unregister_listeners` functions.
* Added `listeners.enable_listeners` and `listeners.disable_listeners` context
managers.
* Avoid crash when looking for anchors in response content.
* Avoid possible failures when checking internal links depending on
ALLOWED_HOSTS setting.
* Confirmed compatibility with Django 3.1.
* Dropped support for Python 3.4.

* Dropped support for Python 2 and Django < 1.11.
* Added support for Django 3.0.
* Made more usage of the requests library.

* Use requests library when getting 'certificate verify failed' errors.
* Fixed compatibility issues with newer versions of Django.
* Fixed pip installation issues with encoding errors (87).

* Added support for `tel:` links.
* For redirecting links, linkcheck now reports the status of the redirect
target (78).
* Dropped South migrations.
* 'Url.redirect_to' was migrated to a TextField to not limit its length (75).
* Fixed handling of the '--limit' argument of the 'checklinks' command (73).
* Fixed the task queue of links to check (69).