private static Path getConfigFile(Path config) {
		if (config == null) {
			config = findNearestLocalConfig();
			if (config == null) {
				config = Settings.getUserConfigFile();
			}
		}
		return config;
	}
Will either return the path to the given config or search for the nearest
config starting from cwd.

@param config The config to return or null to return the nearest config
@return Path to a config
src/main/java/dev/jbang/util/ConfigUtil.java