chore(main): release 2.21.0 (#590) #670

Job	Run time
Examples	5m 23s
linux (5.10)	3m 43s
xcodebuild (test, IOS, 15.4)	8m 47s
xcodebuild (test, IOS, 16.0)	8m 51s
xcodebuild (test, MAC_CATALYST, 15.4)	4m 38s
xcodebuild (test, MAC_CATALYST, 16.0)	6m 4s
xcodebuild (test, MACOS, 15.4)	4m 42s
xcodebuild (test, MACOS, 16.0)	4m 23s
xcodebuild (test, TVOS, 15.4)	7m 31s
xcodebuild (test, TVOS, 16.0)	5m 47s
xcodebuild (test, WATCHOS, 15.4)	7m 44s
xcodebuild (test, WATCHOS, 16.0)	6m 44s
xcodebuild (IOS, 15.4)	4m 11s
xcodebuild (IOS, 16.0)	4m 56s
xcodebuild (MAC_CATALYST, 15.4)	4m 24s
xcodebuild (MAC_CATALYST, 16.0)	4m 34s
xcodebuild (MACOS, 15.4)	4m 14s
xcodebuild (MACOS, 16.0)	5m 29s
xcodebuild (TVOS, 15.4)	4m 27s
xcodebuild (TVOS, 16.0)	4m 24s
xcodebuild (WATCHOS, 15.4)	5m 8s
xcodebuild (WATCHOS, 16.0)	7m 20s
	2h 3m 24s

Provide feedback