Convert to ESLint 9 flat config and move to pnpm, use .mjs and new jest types #6027

	name: javascript / format

	on:
	push:
	pull_request:
	workflow_dispatch:

	jobs:
	verify:
	runs-on: ubuntu-22.04
	steps:
	- name: 'Checkout code'
	uses: actions/checkout@692973e3d937129bcbf40652eb9f2f61becf3332
	- name: Use Node.js LTS (18.x)
	uses: actions/setup-node@1e60f620b9541d16bece96c5465dc8ee9832be0b
	with:
	node-version: '18'
	- name: Install project development dependencies
	run: npm i
	- name: 'Verify formatting of all files'
	run: ./bin/check-formatting.sh

Provide feedback