Build and include kani-cov in the bundle

[adpaco-aws]

This PR adds another step to the cargo bundle command so that kani-cov is built in release mode and then included in the bundle. This will allow users to call kani-cov once Kani has been setup.

I have manually tested it works by running:

cargo bundle
tar -xzf kani-0.56.0-x86_64-unknown-linux-gnu.tar.gz
ls kani-0.56.0/bin/

This showed kani-cov along with other binaries like cbmc and kissat.

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

[zhassan-aws]

Thanks