Define node compatibility

[aske02]

Node compatibility should be defined in package.json due to scraper.ts using a node >18.0.0 feature global.fetch.
As node 16.x is still used by some people, it could create confusion.
Due to the error not being so detailed when global.fetch is not defined.
The error:

ArgumentError {
  name: 'ArgumentError',
  message: 'fetch must be a function'
}

The suggestion is to add the following to the package.json

"engines": {
	"node": ">=18.0.0"
  },
"engineStrict": true

[luttje]

Hey @aske02, thanks for this report! You are very much right that this confusion should be prevented by the fix you suggest.

Sadly I don't have time to update, but if you can make a PR I'll be happy to merge. Otherwise I'll have a look in a month or so.

Thanks