code: public Version with(Qualifier qualifier, int qualifierNumber) {
      this.qualifier = defaultIfNull(qualifier, Qualifier.UNDEFINED);
      this.qualifierNumber = Math.max(qualifierNumber, 0);
      return this;
    }
docs: Sets the {@link Version.Qualifier} for this {@link Version}.
  
  @param qualifier {@link Version.Qualifier}.
  @param qualifierNumber {@link Version.Qualifier} number.
  @return this {@link Version} reference.