Added support for user-defined keycodes

[jsherlockppb]

Hi,

Here's a PR for your consideration, which allows users to specify additional keycodes which trigger adding a tag based on the current input value. Currently, this only happens with the user presses Enter (13), but this change allows users to specify an optional array of additionalKeycodes which can result in a tag being added e.g. comma, space, tab etc.

I have updated example/index.tsx accordingly to illustrate how this would work. The new property is optional and so has no impact on the current functionality if it is not provided.

const initialSettings: ReactTagInputProps = {
  tags: [],
  onChange: (tags) => {},
  placeholder: "Type and press enter, tab, space or comma",
  maxTags: 10,
  editable: true,
  readOnly: false,
  removeOnBackspace: true,
  validator: undefined,
  additionalKeycodes: [9, 32, 188]  // tab, space, comma
};

Thanks,

J

[jsherlockppb]

Ah, I've just spotted there is another PR open which provides similar functionality. Please consider merging that. I'll close this one now. Thanks.