build: remove node-fetch (#45)

# Motivation

Fetch API is supported in NodeJS since v18 and stable since v21. Given
that the engine is set to v20 here and given what we are doing, as think
it's probably fine to remove the `node-fetch` (we can run a "next" CI
job to double check).

Update: Job worked out
https://github.com/dfinity/verifiable-credentials-sdk/actions/runs/9869137332/job/27252340286

js-library/package.json

@@ -65,7 +65,6 @@
     "eslint-config-standard": "^17.1.0",
     "eslint-plugin-import": "^2.29.1",
     "eslint-plugin-promise": "^6.1.1",
-    "node-fetch": "^3.3.2",
     "prettier": "^3.2.5",
     "prettier-plugin-organize-imports": "^3.2.4",
     "typescript": "^5.4.5",

js-library/scripts/update-version.mjs

@@ -1,5 +1,4 @@
 import { existsSync, readFileSync, writeFileSync } from "fs";
-import fetch from "node-fetch";
 import { join } from "path";
 
 // The suffix we use to publish to npm wip version of the libs