Prepare for release: v5.6.3 (#10221)

* Bump version: 5.6.2 → 5.6.3

* ci: enable CI on v5.6.x branch

* Added Changelog for v5.6.3

Prepare for release: v5.6.2 (#10049)

* Bump version: 5.6.1 → 5.6.2

* Added Changelog for v5.6.2

Prepare for release: v5.6.1 (#10037)

* Bump version: 5.6.0 → 5.6.1

* Added Changelog for v5.6.1

Prepare for release: v5.6.0 (#10010)

* Bump version: 5.6.0rc2 → 5.6.0

* Added Changelog for v5.6.0

* Fix Sphinx 9.0+ compatibility (released during release checklist tests)

Prepare for (pre) release: v5.6.0rc2 (#10005)

* Bump version: 5.6.0rc1 → 5.6.0rc2

* Added Changelog for v5.6.0rc2

Prepare for (pre) release: v5.6.0rc1 (#9982)

* Bump version: 5.6.0b2 → 5.6.0rc1

* Added Changelog for v5.6.0rc1

Prepare for (pre) release: v5.6.0b2 (#9938)

* Bump version: 5.6.0b1 → 5.6.0b2

* Added Changelog for v5.6.0b2

* Remove Python 3.8 support from the release docs and update Kombu to v5.6.0rc2 (minimum version)

Prepare for (pre) release: v5.6.0b1 (#9890)

* Bump version: 5.5.3 → 5.6.0b1

* Immunity -> Recovery

* Added Changelog for v5.6.0b1

Prepare for release: v5.5.3 (#9732)

* Bump version: 5.5.2 → 5.5.3

* Added Changelog for v5.5.3

Prepare for release: v5.5.2 (#9675)

* Bump version: 5.5.1 → 5.5.2

* Added Changelog for v5.5.2