code: public Version setNumber(int index, int number, String label) {
          validateNumber(number);
          if (isBeyondBounds(index)) {
              String message = String.format("illegal number index: %d", index);
              throw new IllegalArgumentException(message);
          }
          labels.set(--index, label);
          numbers.set(index, number);
          return this;
      }
docs: Sets a new version number.
  
  @param index available version number index.
  @param number version number (not negative).
  @param label version number label (optional).
  @return version descriptor.
  @throws IllegalArgumentException if either index or number are illegal.
  
  @since v1.1.0