Use the runner v3 API [ONPREM-237]

[christian-stephen]

Checklist

=========

• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have checked for similar issues and haven't found anything relevant.
• This is not a security issue (which should be reported here: https://circleci.com/security/)
• I have read Contribution Guidelines.

Internal Checklist

• I am requesting a review from my own team as well as the owning team
• I have a plan in place for the monitoring of the changes that I am making (this can include new monitors, logs to be aware of, etc...)

Changes

=======

• Update the runner CRUD operations to use the runner v3 API instead of v2

Rationale

=========

What was the overarching product goal of this PR as well as any pertinent
history of changes

The runner v2 API is being actively deprecated and will be EoL soon, so the CLI needs to be updated to provide a migration path for CircleCI runner users.

Considerations

==============

Why you made some of the technical decisions that you made, especially if the
reasoning is not immediately obvious

Server 4.6 just recently shipped, marking 4.2 as unsupported. This was the last version that didn't support the runner v3 API.

Screenshots

============

Before

Image or [gif](https://giphy.com/apps/giphycapture)

After

Image or gif where change can be clearly seen

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