Support Node LTS

Running this example:

const { Deno } = require("deno.ns");

I get the following in Node v14.17.1:

> node test.js
node_modules\deno.ns\dist\deno\stable\classes\PermissionStatus.js:7
class PermissionStatus extends EventTarget {
                               ^

ReferenceError: EventTarget is not defined
    at Object.<anonymous> (node_modules\deno.ns\dist\deno\stable\classes\PermissionStatus.js:7:32)
    at Module._compile (internal/modules/cjs/loader.js:1085:14)
    at Object.Module._extensions..js (internal/modules/cjs/loader.js:1114:10)
    at Module.load (internal/modules/cjs/loader.js:950:32)
    at Function.Module._load (internal/modules/cjs/loader.js:790:14)
    at Module.require (internal/modules/cjs/loader.js:974:19)
    at require (internal/modules/cjs/helpers.js:92:18)
    at Object.<anonymous> (node_modules\deno.ns\dist\deno\stable\classes\Permissions.js:5:31)
    at Module._compile (internal/modules/cjs/loader.js:1085:14)
    at Object.Module._extensions..js (internal/modules/cjs/loader.js:1114:10)

This is because EventTarget was not a global until node v15 I think (works in 16). Current LTS version of node is v14. We should try to support at least Node LTS.

[bartlomieju]

Node v14 goes into maintenance period today and Node v16 becomes LTS in a week https://nodejs.org/en/about/releases/

I think we should focus on v16

[MKRhere]

Alternatively, node 16 is active LTS from end of this month (October 26th). Since deno.ns might not be “stable” for a few weeks even by the most optimistic estimate, it might not be so bad to only support active LTS from then (node 16).