Gracefully handle the case where a non-existant project is provided on the CLI

[godber]

When I supply a github user and project that doesn't exist I get a stack trace:

./bin/fetch-github-release -d -o json trycua luma
HTTPError: Response code 404 (Not Found)
    at Request.<anonymous> (file:///Users/godber/Workspace/terascope/opensource/fetch-github-release/node_modules/got/dist/source/as-promise/index.js:86:42)
    at Object.onceWrapper (node:events:634:26)
    at Request.emit (node:events:531:35)
    at Request._onResponseBase (file:///Users/godber/Workspace/terascope/opensource/fetch-github-release/node_modules/got/dist/source/core/index.js:726:22)
    at process.processTicksAndRejections (node:internal/process/task_queues:105:5)
    at async Request._onResponse (file:///Users/godber/Workspace/terascope/opensource/fetch-github-release/node_modules/got/dist/source/core/index.js:768:13) {
  input: undefined,
  code: 'ERR_NON_2XX_3XX_RESPONSE',

It should do the following things in these cases:

• default txt output - should print a text error message saying the project FOO doesn't exist
• -q - nothing printed
• --json should return:

{
  "error": "Project FOO doesn't exist."  /// same message as above
}

In all cases the return code (echo $?) is set to non-zero (e.g. 1, make sure it's unique and documented in the code that the return code indicates the package doesn't exist.