loadConfig method
Implementation
Future<void> loadConfig() async {
final file = File(configFilePath);
if (!file.existsSync()) {
throw ConfigException("Configuration file `$configFilePath` not found");
}
final contents = await file.readAsString();
final yamlMap = loadYaml(contents);
if (yamlMap == null || !yamlMap.containsKey('fonts')) {
throw ConfigException("Invalid configuration file `$configFilePath`");
}
}