Add kani-version parameter to kani-github-action

[jaisnan]

Description of changes:

This PR updates the action to add the parameter for kani-version which defaults to the value latest.
The default value latest uses the latest version of Kani that is uploaded on crates.io unless a specific version is provided by the user, in which case that specific version of Kani will be used in the CI.

Resolved issues:

Resolves #ISSUE-NUMBER

Call-outs:

This would update the action to pull in the latest version by default. Users who don't provide a value for the kani-version parameter would have to set it to pin the kani version that they want to use.

Testing:

• How is this change tested?

• Is this a refactor change?

Checklist

• Each commit message has a non-empty body, explaining why the change was made
• Methods or procedures are documented
• Regression or unit tests are included, or existing tests cover the modified code
• My PR is restricted to a single feature or bugfix

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 and MIT licenses.