Sunsetting Node 14 and 16 support

[wopian]

Guaranteed Node 14 and 16 support with be removed once the TypeScript rewrite has been completed in #818 as the following Node versions become EOL in 2023:

• Node 14: 30th April 2023
• Node 16: 11th September 2023

Applications that are stuck on using Node 14 will likely continue to function as normal as I don't think there has been any major language features added in Node 16+/modern browsers that are in use by our code that is potentially being polyfilled for compatibility purposes by Babel.

[wopian]

Due to the timeframe the TypeScript rewrite has taken, Node 16 will also be sunset with it, as it became EOL this month (Oct 2023)

#818

@pedep feel free to assist migrating functionality over if you have time. My availability has been slim between work, Zeepkist and my photography work over the past several months 😿

[pedep]

@wopian i have begun refactoring parts of kitsu-core in #930 . Please let me know if you see anything you would like changed.

[pedep]

@wopian any thoughts on removing axios as a direct dependency of kitsu, in favor of using native fetch?
Since we are sunsetting node < 18, we can use fetch native both client and servers-side.

I would suggest moving an axios implementation to a separate package kitsu-axios for everyone with axios specifics in their codebase, such as middleware.

import { Kitsu } from 'kitsu'
import { AxiosAdapter } from 'kitsu-axios'

const api = new Kitsu({adapter: new AxiosAdapter()})

// or

Kitsu.default_adapter = AxiosAdapter;
const api = new Kitsu()

Another option is to add the kitsu-axios package as a dependency of kitsu and set it as the default. Then we can swap the defaults and remove the direct dependency in a later version. This way the current axios implementation sticks around until everyone has had a chance to migrate to fetch, or add a direct dependency on kitsu-axios to continue using axios

import { Kitsu, FetchAdapter } from 'kitsu'

const api = new Kitsu({adapter: new FetchAdapter()})

[wopian]

@pedep yes, ^11 would be a good opportunity to finally get rid of Axios.

The kitsu package is relatively basic so I don't think we'd need to worry about implementing an adapter - it's only a few lines of code outside of all the JSDoc comments, so duplicating that in a seperate package for Axios wouldn't be too non-DRY.

kitsu could be soley native fetch from ^11 onwards and kitsu-axios would be an identical implementation with Axios ^1.x instead. So your upgrade paths from kitsu@9 and kitsu@10 (both Axios ^0.x) are either native Fetch or Axios ^1

[wopian]

Eslint v9 dev dependency drops support for Node 16, so this package will be pinned to v8 until Kitsu v11