ci: remove macos-11 runner #326

Job	Run time
cocoapods	1m 36s
swiftpm (iphoneos, arm64)	26s
example (Maps)	1m 8s
swiftpm (iphonesimulator, x86_64)	34s
build (5.10, 15.4, macos-14)	50s
swiftpm_old (x86_64-apple-ios16.4-simulator, 14.3.1, macos-13)	37s
example (Maps-SwiftUI)	46s
swiftpm (iphonesimulator, arm64)	20s
build (5.9, 15.2, macos-13)	42s
swiftpm_old (arm64-apple-ios16.4-simulator, 14.3.1, macos-13)	38s
example (Stocks)	1m 5s
build (5.8, 14.3.1, macos-13)	55s
swiftpm_old (x86_64-apple-ios15.7-simulator, 14.1, macos-12)	1m 6s
example (Samples)	1m 48s
build (5.7, 14.1, macos-12)	39s
swiftpm_old (arm64-apple-ios15.7-simulator, 14.1, macos-12)	42s
test (17.5, 15.4, iPhone 15 Pro, NO, macos-14)	3m 32s
build (5.6, 13.4.1, macos-12)	33s
test (16.4, 14.3.1, iPhone 14 Pro, NO, macos-13)	4m 32s
build (5.5, 13.2.1, macos-12)	2m 11s
test (15.5, 13.4.1, iPhone 13 Pro, NO, macos-12)	4m 28s
	29m 8s

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