chore: update GitHub Actions CI

[striezel]

The following updates are performed:

• update actions/cache to v3
• update actions/checkout to v4

Still using the outdated actions will generate several warnings in CI runs, for example in https://github.com/RichoDemus/bevy-console/actions/runs/5556537669:

The following actions use node12 which is deprecated and will be forced to run on node16: actions/checkout@v2, actions/cache@v2. For more info: https://github.blog/changelog/2023-06-13-github-actions-all-actions-will-run-on-node16-instead-of-node12-by-default/

The PR will get rid of those warnings.

[striezel]

I just force pushed some changes, because meanwhile v4 of actions/checkout has been released, so the PR should use that newer version.