Add support for newer emoji, such as skin swatches

[kattrali]

The current emoji data list does not include skin swatches for the equivalent text, such as :skin_tone_2:

[oblitum]

Now that it seems colored emojis are generally available in a bunch of distros and I'm seeing them in terminal a lot, I've noticed that there's a bunch that isn't covered here but that could be enabled.

[hakanai]

Is this as simple as adding the mappings to the code?

I tried doing it for a :skin-tone-2: I found, but the result doesn't seem any different than the same emoji without the skin tone modifier.

[ghost]

another option is to read json file to add emojis on demand like: https://github.com/wee-slack/wee-slack/blob/master/weemoji.json