feat(cli)!: rename --cdktf-version in init

[gabegorelick]

The init CLI command currently accepts a --cdktf-version option. This change renames it to --cdktn-version.

Related issue

Fixes #

Description

cdktn init --cdktf-version -> cdktn init --cdktn-version

This is a breaking change, but should hopefully not be too disruptive.

Checklist

• I have updated the PR title to match CDKTN's style guide
• I have run the linter on my code locally
• I have performed a self-review of my code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation if applicable
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works if applicable
• New and existing unit tests pass locally with my changes

[jsteinich]

Can you also prep a PR on https://github.com/open-constructs/cdk-terrain-docs about the change?

Likely going to hold this a bit since I think we'll have at least one more release before introducing breaking changes.

[jsteinich]

Won't this now ignore having an empty string set for fromTerraformProject while previously it would have errored?

[gabegorelick]

The "" case was included in the .includes before, but it's now covered in the argv.fromTerraformProject conditional. The latter is needed for Typescript to discern that that field is defined.

[gabegorelick]

Can you also prep a PR on https://github.com/open-constructs/cdk-terrain-docs about the change?

open-constructs/cdk-terrain-docs#13

Side note, it would be nice if the docs were merged into this repo so we didn't have split commits.