Pelican

* Add new URL pattern to `PAGINATION_PATTERNS` for the last page in the list (1401)
* Speed up `livereload` Invoke task via caching (2847)
* Ignore `None` return value from `get_generators` signal (2850)
* Relax dependency minimum versions and remove upper bounds

Replace plugin definitions in settings with string representations after registering, so they can be cached correctly (2828).

Fix a mistake made in PR 2821

Improve logging of generators and writer loaders

* Refactor intra-site link discovery in order to match more permissively [2646](https://github.com/getpelican/pelican/issues/2646)
* Fix plugins running twice in auto-reload mode [2817](https://github.com/getpelican/pelican/issues/2817)
* Add notice to use `from pelican import signals` instead of `import pelican.signals` [2805](https://github.com/getpelican/pelican/issues/2805)

* List registered plugins via ``pelican-plugins`` command
* Override settings via ``-e`` / ``--extra-settings`` CLI option flags
* Add settings for custom Jinja globals and tests
* Customize article summary ellipsis via `SUMMARY_END_SUFFIX` setting
* Customize Typogrify dash handling via new `TYPOGRIFY_DASHES` setting
* Support Unicode when generating slugs
* Support Asciidoc `.adoc` file generation in Pelican importer
* Improve user experience when `pelican --listen` web server is quit
* Improve Invoke tasks template
* Include tests in source distributions
* Switch CI from Travis to GitHub Actions
* Remove support for Python 2.7

For more information, including upgrade instructions, please refer to the [release announcement](https://blog.getpelican.com/pelican-4.5-released.html).