Provide def file for windows import lib

[Pospelove]

closes #15

example PR created by updated workflow: Pospelove#2

[Pospelove]

let's merge

[Pospelove]

@mhdawson @legendecas

[legendecas]

Thanks for the work. Looks good to me.

@vmoroz and @NickNaso mentioned that they are able to take a look at this. As this has been open for weeks, I'll land this as is tomorrow if no changes are requested.

[NickNaso]

Hi @Pospelove,
maybe it could be better to put the definition files in a folder like def and then update the index.js in something like repoterd below:

'use strict'

const path = require('path');
const symbols = require('./symbols')

const include_dir = path.resolve(__dirname, 'include');

const js_native_def = path.resolve(__dirname, 'def','js_native_api.def');
const node_api_def = path.resolve(__dirname, 'def', 'node_api.def');
const def = {
    js_native_def,
    node_api_def
}

module.exports = {
    include_dir,
    symbols,
    def
}

What do you think about?
If you agree with my proposal please update the documentation https://github.com/nodejs/node-api-headers/pulls#api