deps: bump croner from 3.0.1 to 4.0.0

[dependabot]

Bumps croner from 3.0.1 to 4.0.0.

Release notes

Sourced from croner's releases.

4.0.0

Croner 4.0.0 Release Notes

Major Features & New Backends

• Generic CronDateTime Trait & Jiff Support: Introduced a backend-agnostic CronDateTime trait by @​ion-elgreco (#48), adding an optional, high-performance jiff datetime backend alongside chrono (#49). The chrono backend is now placed behind an optional feature flag (enabled by default).
• LW & 31W Support: Added support for the LW (last weekday) pattern and verified 31W behavior ([#37](Hexagon/croner-rust#37)).
• OCPS-Compliant Validation: Added OCPS-compliant step syntax validation with an optional sloppy_ranges mode ([#39](Hexagon/croner-rust#39)).
• Derive Traits: Derived Eq and Ord implementations for Cron by @​CardboardTurkey ([#43](Hexagon/croner-rust#43)).

Improvements, Bug Fixes & Refactoring

• Performance & Hot Paths: Cut redundant work out of the day-matching hot path by @​ion-elgreco ([#46](Hexagon/croner-rust#46)) and refactored day matching to use a weekday value instead of a calendar type ([#47](Hexagon/croner-rust#47)).
• DST Iteration Fixes: Fixed iteration during DST overlap and Jiff DST handling by @​ion-elgreco ([#53](Hexagon/croner-rust#53)).
• Chrono Feature Reduction: Reduced features of chrono by @​paolobarbolini ([#42](Hexagon/croner-rust#42)) and isolated it behind a feature flag.
• Testing & Documentation: Added test verification for case-insensitivity of aliases and modifiers ([#40](Hexagon/croner-rust#40)), added a Quartz Compatibility section ([#41](Hexagon/croner-rust#41)), and updated README and simple_demo to use the Jiff backend ([#52](Hexagon/croner-rust#52)).

---

Breaking Changes & Migration Guide

Version 4.0 introduces architectural upgrades that may require code adjustments. For complete details, consult the official https://github.com/hexagon/croner-rust/blob/HEAD/MIGRATION.md guide. Key breaking changes include:

• Optional Chrono Feature: chrono is now an optional feature flag (enabled by default). If your project compiles with default-features = false, you must explicitly add "chrono" or "jiff" to your Cargo.toml.
• Stricter Step Syntax Validation: Shortcut step syntax (e.g., 5/5 * * * *) is now rejected by default and requires explicit ranges like 5-59/5 * * * *. You can restore the old lenient behavior by building your parser with .sloppy_ranges(true).
• Generic Datetime Methods: Methods now bind on the new CronDateTime trait instead of chrono::TimeZone. Return types match the input type. When type inference is ambiguous (e.g., with multiple backends enabled), a turbofish annotation may be needed:

let next = cron
    .find_next_occurrence::<chrono::DateTime<chrono::Utc>>(&chrono::Utc::now(), false)
    .unwrap();

• Removed/Deprecated APIs:
• The internal tuple-returning find_occurrence method has been removed from the public API; use find_next_occurrence instead.
• The crate-level croner::from_naive function is deprecated; use chrono::TimeZone::from_local_datetime directly.
• CronIterator<Tz> has been renamed to CronIterator<T>.

---

New Contributors

• @​paolobarbolini made their first contribution in [#42](Hexagon/croner-rust#42)
• @​ion-elgreco made their first contribution in [#46](Hexagon/croner-rust#46)

Full Changelog: Hexagon/croner-rust@v3.0.1...v4.0.0

Changelog

Sourced from croner's changelog.

[4.0.0]

Added

• Added backend-agnostic searching through the CronDateTime trait and shared civil-time abstractions.
• Added an optional jiff backend, simple_demo_jiff, and backend parity coverage.
• Added OCPS-focused coverage for LW, +, and strict step-syntax validation.
• Added a dedicated migration guide for 3.x to 4.0 upgrades.
• Added regression tests for backward searches across DST gaps.

Changed

• Made the chrono backend optional while keeping it enabled by default.
• Made occurrence-finding APIs generic over the input datetime type.
• Tightened default step parsing to the OCPS-compliant forms, with sloppy_ranges(true) available for backward compatibility.

Fixed

• Fixed DST overlap iteration and search ordering for both backends.
• Fixed backward fixed-time searches in DST gaps so they return the post-gap scheduled instant instead of a pre-gap placeholder.
• Refined README and example guidance for the 4.0 backend split.

Commits

• 9babd91 Prepare 4.0 #2 (#55)
• 0d8dc9d Preparations for 4.0.0 (#54)
• 1d08347 Update README and simple_demo to use Jiff backend (#52)
• d73190c Merge pull request #53 from ion-elgreco/fix/dst-iteration
• b6a0993 fix: dst iteration for jiff
• 7dd71c1 fix: iteration during dst overlap
• 13d8b63 Merge pull request #49 from ion-elgreco/feat/jiff-support
• f9f538d test: cap the parity test at the Unix epoch
• c0ea870 feat: add a jiff backend
• c8bf6a6 build: put the chrono backend behind a feature flag
• Additional commits viewable in compare view

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