Add support for Python 3.14

[otetard]

Test pySigma with Python 3.14 in the test GitHub Actions workflow and update code to support Python 3.14.

---

Changes:

• bool(NotImplemented) used to return True with Python<3.14 with a deprecation warning, now it returns an explicit exception (TypeError: NotImplemented should not be used in a boolean context).
• __annotations__ cannot be used with objects, but only with classes in Python 3.14, use type() to access the class definition.

[Copilot]

Pull Request Overview

This PR updates pySigma to support Python 3.13 and 3.14, while fixing compatibility issues with these versions. It addresses changes in Python's behavior around __annotations__ attribute access and bool(NotImplemented) conversion.

• Fixed __annotations__ access to use type(self).__annotations__ instead of self.__annotations__ for proper attribute resolution in class hierarchies
• Added exception handling for TypeError when calling comparison operators that may return NotImplemented in Python 3.14
• Updated PyYAML dependency to version 6.0.3 for Python 3.13/3.14 compatibility

Reviewed Changes

Copilot reviewed 5 out of 6 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
sigma/types.py	Fixed __annotations__ access in to_plain() method to use class-level annotations
sigma/processing/transformations/values.py	Fixed __annotations__ access in RegexTransformation and CaseTransformation validation
sigma/processing/conditions/rule.py	Added TypeError exception handling for comparison operations returning NotImplemented
pyproject.toml	Added Python 3.13 and 3.14 classifiers, updated pyyaml minimum version to 6.0.3
poetry.lock	Updated PyYAML package lock entries to version 6.0.3
.github/workflows/test.yml	Added Python 3.14 to CI test matrix