e3f409e3c4 ci: update Kani GitHub Actions runners to ubuntu-24.04 (Erick Cestari)
Pull request description:
GitHub is deprecating the ubuntu-20.04 runner, with removal scheduled for 2025-04-01 (see [GitHub Issue #11101](https://github.com/actions/runner-images/issues/11101)).
This PR updates the CI/CD workflows to use ubuntu-24.04 instead of ubuntu-20.04 for the following workflows:
- cron-daily-kani.yml
- rust.yml (Kani codegen job)
This change should resolve the CI/CD error in the Kani codegen - stable toolchain job triggered by pull requests.
ACKs for top commit:
Kixunil:
ACK e3f409e3c4
apoelstra:
ACK e3f409e3c4327c647b64416caa401c883b459c86; successfully ran local tests
Tree-SHA512: 7e235b68226042937e7269cccae4850cd33cc09c1546a068542903bf9756aaf77155fce3991f899b8470bc97a7115c7ed22e4f09a4c4f4061897a0b18a993487