fix(deps): Update dependency structlog to v25.4.0 (#328)

This PR contains the following updates:

| Package | Update | Change |
|---|---|---|
| [structlog](https://redirect.github.com/hynek/structlog) ([changelog](https://redirect.github.com/hynek/structlog/blob/main/CHANGELOG.md)) | minor | `==25.1.0` -> `==25.4.0` |

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### Release Notes

<details>
<summary>hynek/structlog (structlog)</summary>

### [`v25.4.0`](https://redirect.github.com/hynek/structlog/blob/HEAD/CHANGELOG.md#2540---2025-06-02)

[Compare Source](https://redirect.github.com/hynek/structlog/compare/25.3.0...25.4.0)

##### Added

-   Support for Python 3.14 and Python 3.13.4.

    Python 3.14 has an backwards-incompatible change to `logging.Logger.isEnabledFor()` (it now always returns False if a log entry is in flight) that has been backported to 3.13.4 (expected on 2025-06-03).
    It mainly affects `structlog.stdlib.filter_by_level()`.
    [#&#8203;723](https://redirect.github.com/hynek/structlog/pull/723)

-   `structlog.tracebacks` now handles [exception groups](https://docs.python.org/3/library/exceptions.html#exception-groups).
    `structlog.tracebacks.Stack` has two new fields, `is_group: bool` and `exceptions: list[Trace]`.
    This works similarly to what Rich v14.0.0 does.
    [#&#8203;720](https://redirect.github.com/hynek/structlog/pull/720)

##### Fixed

-   `structlog.processors.ExceptionPrettyPrinter` now respects the *exception_formatter* arguments instead of always using the default formatter.
    [#&#8203;724](https://redirect.github.com/hynek/structlog/pull/724)

### [`v25.3.0`](https://redirect.github.com/hynek/structlog/blob/HEAD/CHANGELOG.md#2530---2025-04-25)

[Compare Source](https://redirect.github.com/hynek/structlog/compare/25.2.0...25.3.0)

##### Fixed

-   `structlog.processors.TimeStamper` now again uses timestamps using UTC for custom format strings when `utc=True`.
    [#&#8203;713](https://redirect.github.com/hynek/structlog/pull/713)

### [`v25.2.0`](https://redirect.github.com/hynek/structlog/blob/HEAD/CHANGELOG.md#2520---2025-03-11)

[Compare Source](https://redirect.github.com/hynek/structlog/compare/25.1.0...25.2.0)

##### Added

-   `structlog.tracebacks.Stack` now includes an `exc_notes` field reflecting the notes attached to the exception.
    [#&#8203;684](https://redirect.github.com/hynek/structlog/pull/684)

##### Changed

-   `structlog.stdlib.BoundLogger`'s binding-related methods now also return `Self`.
    [#&#8203;694](https://redirect.github.com/hynek/structlog/pull/694)

-   `structlog.processors.TimeStamper` now produces internally timezone-aware `datetime` objects.
    Default output hasn't changed, but you can now use `%z` in your *fmt* string.
    [#&#8203;709](https://redirect.github.com/hynek/structlog/pull/709)

##### Fixed

-   Expose `structlog.dev.RichTracebackFormatter` for imports.
    [#&#8203;699](https://redirect.github.com/hynek/structlog/pull/699)
-   Expose `structlog.processors.LogfmtRenderer` for imports.
    [#&#8203;701](https://redirect.github.com/hynek/structlog/pull/701)

</details>

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Author: cq-bot

setup.py

@@ -28,7 +28,7 @@
     "python-dateutil>=2.8.1",
     "pytz==2025.2",
     "six==1.17.0",
-    "structlog==25.1.0",
+    "structlog==25.4.0",
     "tomli==2.2.1",
     "tzdata==2025.1",
 ]