Bump version: 4.3.0rc3 → 4.3.0

Fixes celery#5180.

Bump version: 4.3.0rc2 → 4.3.0rc3

Bump version: 4.2.1 → 4.2.2

Bump version: 4.3.0rc1 → 4.3.0rc2

Bump version: 4.2.1 → 4.3.0rc1

Bump version: 4.2.0 → 4.2.1

Added release date to changelog.

Bump version: 4.2.0rc3 → 4.2.0rc4

Bump version: 4.1.0 → 4.1.1

Bump version: 4.2.0rc2 → 4.2.0rc3