Make format and check-parse CLI subcommands consistent

[svanderbleek]

Description of changes

Issue #403

Based on discussion of format and check-parse in linked issue, specifically:

If we make format use -p and --policies instead of a positional argument, then I think we can call it good.

This should close that issue out by making the two subcommands consistent. It only requires a small renaming change for format in the code. I updated the changelog to note the removal of the positional argument for format.

Checklist for requesting a review

The change in this PR is:

• A breaking change requiring a major version bump to cedar-policy (e.g., changes to the signature of an existing API).

I confirm that this PR:

• Updates the "Unreleased" section of the CHANGELOG with a description of my change (required for major/minor version bumps).

I confirm that cedar-spec:

• Does not require updates because my change does not impact the Cedar Dafny model or DRT infrastructure.

Disclaimer

By submitting this pull request, I confirm that you can use, modify, copy, and redistribute this contribution, under the terms of your choice.

[john-h-kastner-aws]

Looks good. Thanks again!

[svanderbleek]

Cool, just had a to fix a failing test I missed for the positional change.

[svanderbleek]

I don't understand what the "Build Downstream Dependencies" is doing.

[john-h-kastner-aws]

Failing downstream is due to #393. Nothing to fix here.