[ruby] Update Ruby 4.0.0 → 4.0.1

[depfu]

Here is everything you need to know about this upgrade. Please take a good look at what changed and the test results before merging this pull request.

What changed?

Release Notes

4.0.1

Posted by k0kubun on 13 Jan 2026

      <p>Ruby 4.0.1 has been released.</p>

This release includes a bugfix for spurious wakeup from Kernel#sleep when subprocess exits in another thread, along with other bugfixes. Please see the GitHub releases for further details.

Release Schedule

We intend to release the latest stable Ruby version (currently Ruby 4.0) every two months following the most recent release. Ruby 4.0.2 will be released in March, 4.0.3 in May, 4.0.4 in July, 4.0.5 in September, and 4.0.6 in November.

If a change arises that significantly affects users, a release may occur earlier than planned, and the subsequent schedule may shift accordingly.

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[coveralls]

Pull Request Test Coverage Report for Build 21191886164

Details

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 99.351%

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Totals
Change from base Build 21152743079:	0.0%
Covered Lines:	766
Relevant Lines:	771

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💛 - Coveralls