* Deprecate spider args of spider middleware methods.
* Deprecate the spider arg of pipeline process_item().
* Fix a typing issue.
* Deprecate the spider arg of pipeline {open,close}_spider().
* Cleanup.
* Update docs.
* Add pragma: no cover to some deprecated code.
* More tests.
* More tests.
* More tests.
* Simplify _process_parallel().
* Initial BaseSpiderMiddleware.
* Rename the new methods.
* Remove the spider argument from new BaseSpiderMiddleware methods.
* Add docs for BaseSpiderMiddleware.
* Silence pylint.
* Add BaseSpiderMiddleware tests.
* Add a release note.