fix mistyped persistent_pxe baremetal flag

[jasites]

Description

before:

$ vultr-cli bare-metal create -r ewr -p vbm-24c-256gb-amd --os=1743
Error: error parsing flags for bare metal create : error parsing persistenterrpxe flag for bare metal create : flag accessed but not defined: persistenterrpxe

after:

$ ./builds/vultr-cli_linux_amd64 bare-metal create -r ewr -p vbm-24c-256gb-amd --os=1743
Error: error with bare metal create : {"error":"Server add failed: This plan is currently unavailable in this region. Please choose a different plan.","status":400}

Related Issues

Checklist:

• Have you checked to ensure there aren't other open Pull Requests for the same update/change?
• Have you linted your code locally prior to submission?
• Have you successfully ran tests with your changes locally?

[github-actions]

Unit Tests and Coverage

Show Output

?   	github.com/vultr/vultr-cli/v3	[no test files]

Pusher: @jasites, Action: pull_request_target

[optik-aper]

Good catch!