Add prek hook to auto-update copyright year in NOTICE files

[xchwan]

issue: #60540

Airflow has 170+ NOTICE files that required manual year updates annually (e.g. 2016-2025 → 2016-2026) with no automation in place.

Adds update-notice-year hook

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Was generative AI tooling used to co-author this PR?

• Yes (please specify the tool below)
• Claude Code Sonnet 4.6

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• Read the Pull Request Guidelines for more information. Note: commit author/co-author name and email in commits become permanently public when merged.
• For fundamental code changes, an Airflow Improvement Proposal (AIP) is needed.
• When adding dependency, check compliance with the ASF 3rd Party License Policy.
• For significant user-facing changes create newsfragment: {pr_number}.significant.rst, in airflow-core/newsfragments. You can add this file in a follow-up commit after the PR is created so you know the PR number.

[potiuk]

This will have the undesirble side effect that all PRs will be failing 01.01.2027 when everyone who can help might be partying hard (and not wake up early next day).

I am not sure we want it. If anything - this could be manual prek hook, and we should have workflow scheduled maybe every week or so to check if the year changed and post notification on slack in the #internal-* channel like other notifications. The issue is that it's next to impossible to test before Jan 2027

[xchwan]

I think the simplest fix is to strip the year check out of check_notice_files.py and keep only the ASF declaration check. The scheduled notification approach still requires someone to manually run update_notice_year.py at the end anyway. And if the update is done in late December, Copyright 2016-2027 would be incorrect while still in 2026, which check_notice_files.py would then reject — update early and the year is wrong, wait until 01/01 and everyone is at a New Year's party. So:

• pre-commit only blocks genuine errors where the ASF declaration is missing entirely
• PRs never fail due to year drift
• Someone can run update_notice_year.py when they remember, and nothing explodes if they don't

How do you think about this?