CMake

Add tests for dates known to overlap between ISO8601 and Gregorian years #113

Job	Run time
build (Ubuntu 20.04, ubuntu-20.04)	1m 24s
build (Ubuntu 22.04, ubuntu-22.04)	1m 23s
build (macOS 14, macos-14)	53s
build (macOS 12, macos-12)	1m 37s
build (macOS 13, macos-13)	1m 52s
integration-test (Timewarrior [stable], timew-libshared-stable)	1m 45s
integration-test (Timewarrior [develop], timew-libshared-develop)	1m 41s
integration-test (Taskwarrior [stable], task-libshared-stable)	4m 36s
integration-test (Taskwarrior [develop], task-libshared-develop)	4m 29s
	19m 40s

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