Add PyPI-based pySigma version dependency detection for plugins

[Copilot]

Plugin pySigma version dependencies are currently maintained manually in the plugin directory. This adds methods to fetch dependency info directly from PyPI metadata and automatically find compatible plugin versions.

Changes

• pysigma_version_from_pypi(plugin_version=None) - Fetches pySigma version specifier from PyPI requires_dist metadata for latest or specific plugin version
• find_compatible_version() - Iterates through all PyPI releases (newest first) to find a compatible version for the installed pySigma
• Helper methods _get_pypi_json() and _extract_pysigma_specifier() for PyPI API interaction

Usage

from sigma.plugins import SigmaPlugin

plugin = SigmaPlugin(...)
plugin.package = "pysigma-backend-splunk"

# Get pySigma requirement from PyPI
specifier = plugin.pysigma_version_from_pypi()  # Latest: <2.0,>=1.0
specifier = plugin.pysigma_version_from_pypi("1.1.3")  # Specific: <0.12.0,>=0.11.18

# Find compatible version for current pySigma installation
compatible = plugin.find_compatible_version()  # Returns e.g. "2.0.0"

Warning

Firewall rules blocked me from connecting to one or more addresses (expand for details)

I tried to connect to the following addresses, but was blocked by firewall rules:

• d3fend.mitre.org
  • Triggering command: /home/REDACTED/.cache/pypoetry/virtualenvs/pysigma-Tjs8INP8-py3.12/bin/pytest /home/REDACTED/.cache/pypoetry/virtualenvs/pysigma-Tjs8INP8-py3.12/bin/pytest --tb=short (dns block)
  • Triggering command: /home/REDACTED/.cache/pypoetry/virtualenvs/pysigma-Tjs8INP8-py3.12/bin/pytest /home/REDACTED/.cache/pypoetry/virtualenvs/pysigma-Tjs8INP8-py3.12/bin/pytest --tb=short -q (dns block)

If you need me to access, download, or install something from one of these locations, you can either:

• Configure Actions setup steps to set up my environment, which run before the firewall is enabled
• Add the appropriate URLs or hosts to the custom allowlist in this repository's Copilot coding agent settings (admins only)

Original prompt

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This section details on the original issue you should resolve

<issue_title>Determine pySigma dependency of plugins from package</issue_title>
<issue_description>Currently, the pySigma version dependency of plugins is determined from the plugin directory and has to be maintained manually. This should be changed to determining the plugin dependency directly only from the PyPI package metadata. In addition, if the current version of a plugin is not compatible with an older pySigma version, a matching older version of the plugin should be determined automatically.</issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes Determine pySigma dependency of plugins from package #425

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