add --expunge option to event-type delete

[svix-onelson]

Some small fixups were required to update the version of the svix client lib. Specifically, endpoint version is now optional.

---

Verification for expunge:

$ ./svix-cli event-type list
{
  "data": [
    {
      "archived": false,
      "createdAt": "2023-09-27T00:47:39.841665Z",
      "description": "",
      "featureFlag": null,
      "name": "bar",
      "updatedAt": "2023-09-27T00:47:39.841678Z"
    },
    {
      "archived": false,
      "createdAt": "2023-09-27T00:47:35.572796Z",
      "description": "",
      "featureFlag": null,
      "name": "foo",
      "updatedAt": "2023-09-27T00:47:35.57282Z"
    }
  ],
  "done": true,
  "iterator": "foo",
  "prevIterator": "-bar"
}

$ ./svix-cli event-type delete foo
Are you sure you want to delete the event with id: foo: y
Event Type "foo" Deleted!

$ ./svix-cli event-type delete --expunge bar
Are you sure you want to delete the event with id: bar: y
Event Type "bar" Deleted!

$ ./svix-cli event-type list
{
  "data": [],
  "done": true,
  "iterator": null
}

$ ./svix-cli event-type list --include-archived
{
  "data": [
    {
      "archived": true,
      "createdAt": "2023-09-27T00:47:35.572796Z",
      "description": "",
      "featureFlag": null,
      "name": "foo",
      "updatedAt": "2023-09-27T00:48:10.556405Z"
    }
  ],
  "done": true,
  "iterator": "foo",
  "prevIterator": "-foo"
}

Verification for the endpoint version being optional now:

$ ./svix-cli endpoint create demo --data-url https://example.com/1
{
  "createdAt": "2023-09-27T01:05:42.270296Z",
  "description": "",
  "disabled": false,
  "id": "ep_2VxTTtr068YYOUNEzRTTCtzqhQk",
  "metadata": {},
  "rateLimit": null,
  "uid": null,
  "updatedAt": "2023-09-27T01:05:42.27031Z",
  "url": "https://example.com/1",
  "version": 1
}

$ ./svix-cli endpoint create demo --data-url https://example.com/22 --data-version 22
{
  "createdAt": "2023-09-27T01:07:32.855187Z",
  "description": "",
  "disabled": false,
  "id": "ep_2VxThnLAdOyT9RvlspOhHjoR8Cm",
  "metadata": {},
  "rateLimit": null,
  "uid": null,
  "updatedAt": "2023-09-27T01:07:32.8552Z",
  "url": "https://example.com/22",
  "version": 22
}