v0.16.0

Updates various version specs, including the 1.21 latest:

• v1.22: 0.0.0 -> 1.22.0-alpha.0
• v1.21: 1.21.0-alpha.0 -> 1.21.0
• v1.20: 1.20.1 -> 1.20.6
• v1.19: 1.19.6 -> 1.19.10
• v1.18: 1.18.14 -> 1.18.18
• pre: 1.21.0-alpha.0 -> 1.22.0-alpha.0
• latest: 1.20.1 -> 1.21.0