Install Kani into the action, instead of using a docker

[danielsn]

Description of changes:

Currently, the action requires a docker, which is not yet published. Instead, as a temporary solution, just install the dependencies every time.

Resolved issues:

Resolves #1589

Related RFC:

Optional #ISSUE-NUMBER.

Call-outs:

• Installing the dependencies takes about 1-1.5 minutes according to some initial testing.

Testing:

• How is this change tested? Made a repo with Kani proofs, ran this action on it.

• Is this a refactor change? No

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.

[celinval]

I do have one concern regarding how we are using our repository. I was puzzled about having the action.yml in the root of the repository. So I decided to read a bit more about actions. This is basically the first thing in their documentation:

When you plan to publish your action to GitHub Marketplace, you'll need ensure that the repository only includes the metadata file, code, and files necessary for the action.

https://docs.github.com/en/actions/creating-actions/publishing-actions-in-github-marketplace

[celinval]

why not push?

[tedinski]

That's a pretty good point. We should have a kani-action repo or something?

[celinval]

Should we retrieve the version from the repository instead? I was also wondering if we should allow users to choose the version they want to use so they can control when to update Kani.

[danielsn]

My thought was action version matches kani-version. So we have kani-action@0.11 matches kani 0.11

[celinval]

@danielsn Can we close this PR since we have published the Action in a different repo?