Ensure reproducible wheel file timestamps

[3pleX-dev]

This PR updates the build_wheel method to ensure consistent timestamps are used when generating wheel files.

While working on improving reproducible builds in nixpkgs#383885, I noticed that the current implementation relies on the system time when creating zip entries. This causes the resulting wheel files to vary between builds, even when the source hasn’t changed.

The fix:

• Uses ZipInfo objects to explicitly control file timestamps
• Respects the SOURCE_DATE_EPOCH convention (standard for reproducible builds)
• Falls back to a fixed date if SOURCE_DATE_EPOCH is not defined

I'm happy to adjust the approach if there’s a better way to handle this — feedback is very welcome.

[philthompson10]

Can you target the develop branch rather than main. Thanks.