Remove coverage workflow

[optik-aper]

Description

Remove the test coverage workflow which has no use at the moment and is outdated.

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		coverage: 0.0% of statements

Pusher: @optik-aper, Action: pull_request_target