code: public PropertiesBuilder set(String propertyName, Object propertyValue) {
      return set(propertyName, String.valueOf(propertyValue));
    }
docs: Sets the named property to the given value.
  
  @param propertyName the name of the property to set.
  @param propertyValue the value to assign to the property.
  @return a reference to this builder.
  @see #set(String, String)