feat: Building both cjs and esm

[agmoss]

This pr introduces the building of both esm and cjs. This is facilitated via a tsconfig.cjs.json

+ {
+  "extends": "./tsconfig.json",
+  "compilerOptions": {
+   "module": "commonjs",
+   "outDir": "dist/cjs"
+  },
+ }

with a modification to tsconfig.json

{
  "compilerOptions": {
+  "module": "ES2020",
+   "outDir": "dist/esm",
-    "outDir": "dist",
 },
}

and corresponding package.json amendments

+  "main": "dist/cjs/random.js",
+ "module": "dist/esm/random.js",
+  "types": "dist/cjs/random.d.ts",
-  "main": "dist/random.js",
-  "module": "dist/random.js",
-  "types": "dist/random.d.ts",
 "scripts":{
+ "build": "tsc -p tsconfig.json && tsc -p tsconfig.cjs.json",
+ "build:watch": "tsc -p tsconfig.json && tsc -p tsconfig.cjs.json --watch",
  }

[transitive-bullshit]

ideally, we'd use only a single TS project that's a "composite project".

this will allow us to output both versions with build and watch simultaneously.

see here for an example https://github.com/NotionX/react-notion-x/blob/master/tsconfig.json

[transitive-bullshit]

Thanks, Andrew!

[barraponto]

Using 3.0.3 I see an error with import random from "random" in a Create React App project.
It says:

./node_modules/random/dist/esm/index.js
Module not found: Can't resolve './random' in './node_modules/random/dist/esm'

I've double checked: there is an index.js there, it tries to require('./random').default but fails because there isn't any random.js file in there :(