Intermittent MacOS CI failures

[wmdietl]

Many recent CI builds failed on MacOS only and passed after (several) restarts:

>>> Check for downloader release

> checker-framework-language-server@0.2.0 get-downloader-release
> node ./scripts/get-downloader-release.js

/Users/runner/work/1/s/scripts/get-downloader-release.js:37
        const downloadUrl = jsonResponse.assets[0].browser_download_url;
                                               ^

TypeError: Cannot read properties of undefined (reading '0')
    at IncomingMessage.<anonymous> (/Users/runner/work/1/s/scripts/get-downloader-release.js:37:48)
    at IncomingMessage.emit (node:events:529:35)
    at endReadableNT (node:internal/streams/readable:1400:12)
    at process.processTicksAndRejections (node:internal/process/task_queues:82:21)

Node.js v18.20.4
Download failed.

We should investigate whether there is a way to make this code more resilient.