[deps] Update more stuff, switch to ESM

- Switch to type=module in package.json for vite
- Rename eslintrc.js to .cjs
- Upgrade to Node v20 in CI

.github/workflows/ci.yaml

@@ -15,11 +15,11 @@ jobs:
     - name: Use Node.js ${{ matrix.node-version }}
       uses: actions/setup-node@v4
       with:
-        node-version: 16.x
+        node-version: 20.x
     - name: Install Go
       uses: actions/setup-go@v5
       with:
-        go-version: 1.19.x
+        go-version: 1.21.x
     # We don't have it setup in the Makefile to avoid double-building, but 'make lint'
     # requires the react build to have completed.
     - run: make react

react/package.json

@@ -3,6 +3,7 @@
   "version": "1.0.0",
   "description": "React frontend to Pickup music player",
   "main": "index.js",
+  "type": "module",
   "scripts": {
     "build": "vite build",
     "format": "prettier --write src index.html",

react/vite.config.js

@@ -1,6 +1,6 @@
 /* eslint-disable no-undef */
 import { defineConfig } from "vite";
-const { resolve } = require("path");
+import { resolve } from "node:path";
 
 export default defineConfig({
   plugins: [],