node-fetch makes vercel build fail

[ff6347]

I had several issues in other repos using node-fetch since the v3.x is ESM only which goes not well with repos using typescript. As an alternative to node-fetch i suggest cross-fetch

[04:29:09.369] Cloning github.com/technologiestiftung/wegweiser-frontend (Branch: renovate/major-devdependencies-major, Commit: 45513f8)
[04:29:09.925] Cloning completed: 555.572ms
[04:29:12.491] Restored build cache
[04:29:12.529] Running "vercel build"
[04:29:13.017] Vercel CLI 28.10.0
[04:29:13.362] Detected `package-lock.json` generated by npm 7+...
[04:29:13.374] Installing dependencies...
[04:29:24.165] 
[04:29:24.165] added 34 packages, removed 115 packages, and changed 92 packages in 10s
[04:29:24.165] 
[04:29:24.165] 167 packages are looking for funding
[04:29:24.165]   run `npm fund` for details
[04:29:24.186] Detected Next.js version: 12.3.4
[04:29:24.195] Running "npm run build"
[04:29:24.491] 
[04:29:24.491] > [email protected] build
[04:29:24.491] > npm run downloadCacheData && IS_BUILDING=true next build
[04:29:24.491] 
[04:29:24.786] 
[04:29:24.786] > [email protected] downloadCacheData
[04:29:24.786] > npx ts-node src/scripts/downloadCacheData.ts
[04:29:24.786] 
[04:29:27.579] Error [ERR_REQUIRE_ESM]: Must use import to load ES Module: /vercel/path0/node_modules/node-fetch/src/index.js
[04:29:27.580] require() of ES modules is not supported.
[04:29:27.580] require() of /vercel/path0/node_modules/node-fetch/src/index.js from /vercel/path0/src/lib/requests/getGristTableData.ts is an ES module file as it is a .js file whose nearest parent package.json contains "type": "module" which defines all .js files in that package scope as ES modules.
[04:29:27.580] Instead rename index.js to end in .cjs, change the requiring code to use import(), or remove "type": "module" from /vercel/path0/node_modules/node-fetch/package.json.
[04:29:27.580] 
[04:29:27.580]     at new NodeError (internal/errors.js:322:7)
[04:29:27.580]     at Module._extensions..js (internal/modules/cjs/loader.js:1102:13)
[04:29:27.580]     at Object.require.extensions.<computed> [as .js] (/vercel/path0/node_modules/ts-node/src/index.ts:1608:43)
[04:29:27.580]     at Module.load (internal/modules/cjs/loader.js:950:32)
[04:29:27.580]     at Function.Module._load (internal/modules/cjs/loader.js:790:12)
[04:29:27.581]     at Module.require (internal/modules/cjs/loader.js:974:19)
[04:29:27.581]     at require (internal/modules/cjs/helpers.js:101:18)
[04:29:27.581]     at Object.<anonymous> (/vercel/path0/src/lib/requests/getGristTableData.ts:1:1)
[04:29:27.581]     at Module._compile (internal/modules/cjs/loader.js:1085:14)
[04:29:27.581]     at Module.m._compile (/vercel/path0/node_modules/ts-node/src/index.ts:1618:23) {
[04:29:27.581]   code: 'ERR_REQUIRE_ESM'
[04:29:27.581] }
[04:29:27.621] Error: Command "npm run build" exited with 1