Adding a note about DNS to the generic HTTP error message

[SpencerKaiser]

Fixes #257

[SpencerKaiser]

Updated error after latest push:

Internal Error: Error when performing the request to https://registry.yarnpkg.com/yarn/-/yarn-1.3.1.tgz; for troubleshooting help, see https://github.com/nodejs/corepack#troubleshooting
    at ClientRequest.<anonymous> (/Users/skaiser/Dev/corepack/dist/corepack.js:43961:9)
    at ClientRequest.emit (node:events:513:28)
    at TLSSocket.socketErrorListener (node:_http_client:502:9)
    at TLSSocket.emit (node:events:513:28)
    at emitErrorNT (node:internal/streams/destroy:151:8)
    at emitErrorCloseNT (node:internal/streams/destroy:116:3)
    at process.processTicksAndRejections (node:internal/process/task_queues:82:21)

and to repro this locally, override your machine's DNS server to be 1.2.3.4.5.6

[aduh95]

LGTM with a few nits. Can we remove the unrelated changes? We can take them to a separate PR if you want.

[SpencerKaiser]

@aduh95 done! Sorry; I was just worried the CI would fail but it looks like there isn't an action for that 😬 I'll go open an issue