v5.2.0b2

Release date: 2021-08-17 5.35 P.M UTC+3:00

Release by: Omer Katz

• Test windows on py3.10rc1 and pypy3.7 (#6868).
• Route chord_unlock task to the same queue as chord body (#6896).
• Add message properties to app.tasks.Context (#6818).
• handle already converted LogLevel and JSON (#6915).
• 5.2 is codenamed dawn-chorus.
• Bump version: 5.2.0b1 → 5.2.0b2.