build(deps): bump actions/checkout from 3 to 4 #510

Job	Run time
spm-test	6m 1s
linux	2m 54s
windows	4m 26s
test (platform=iOS\ Simulator,name=iPhone\ 14\ Pro\ Max, test)	24m 2s
test (platform\=tvOS\ Simulator,name\=Apple\ TV, test)	7m 39s
test (platform=watchOS\ Simulator,name=Apple\ Watch\ Series\ 5\ \(40mm\), build)	2m 11s
test (platform=macOS, test)	8m 11s
xcode-test-5_5	1m 31s
cocoapods	8m 17s
docs	1m 53s
	1h 7m 5s

Provide feedback