Update GitHub actions and switch from Docker Compose to setup-buildx-action

[pujan14]

Changes proposed

Update GitHub Actions to use newer versions of actions and switch from Docker Compose to setup-buildx-action.

Check List (Check all the applicable boxes)

• I sign off on contributing this submission to open-source
• My code follows the code style of this project.
• All new and existing tests passed.
• This PR does not contain plagiarized content.
• The title of my pull request is a short description of the requested changes.

Note to reviewers

docker compose is already installed on runners.

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[zeevmoney]

Thanks for the cleanup, @pujan14. We're going to close this in favor of #898, which takes the same direction (updating the workflow actions and dropping the manual docker-compose install) but pins actions to full SHA digests, which is the supply-chain hardening standard we want to follow rather than floating major tags. This PR's non-Alpine E2E job is also currently failing. We genuinely appreciate the contribution — the docker-compose removal and pip caching ideas are folded into the consolidated effort.