public static boolean isBuiltIn(String taskType) {
        return BUILT_IN_TASKS.contains(taskType);
    }
Converts a task type string to {@link TaskType}. For an unknown string, the value is
defaulted to {@link TaskType#USER_DEFINED}.

<p>NOTE: Use {@link Enum#valueOf(Class, String)} if the default of USER_DEFINED is not
necessary.

@param taskType The task type string.
@return The {@link TaskType} enum.
common/src/main/java/com/netflix/conductor/common/metadata/tasks/TaskType.java