Use Julia v1.12 for some CI

[ytdHuang]

Checklist

Thank you for contributing to QuantumToolbox.jl! Please make sure you have finished the following tasks before opening the PR.

• Please read Contributing to Quantum Toolbox in Julia.
• Any code changes were done in a way that does not break public API.
• Appropriate tests were added and tested locally by running: make test.
• Any code changes should be julia formatted by running: make format.
• All documents (in docs/ folder) related to code changes were updated and able to build locally by running: make docs.
• (If necessary) the CHANGELOG.md should be updated (regarding to the code changes) and built by running: make changelog.

Request for a review after you have completed all the tasks. If you have not finished them all, you can also open a Draft Pull Request to let the others know this on-going work.

Description

This PR reverses the changes made in PR #560, #561, and #564.

Should be merged after the autodiff packages fix their issues with Julia v1.12.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 92.81%. Comparing base (d44d251) to head (fcd9146).

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #562      +/-   ##
==========================================
- Coverage   93.67%   92.81%   -0.87%     
==========================================
  Files          51       51              
  Lines        3590     3589       -1     
==========================================
- Hits         3363     3331      -32     
- Misses        227      258      +31     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.