chore: SPDX licenses bump automation

[jkowalleck]

fixes #186

this automation will do the following on a daily/scheduled basis

• auto-detect the latest release of SPDX licenses
• update OUR list of known SPDX licenses
• Pull request the changes, if needed

[Copilot]

Pull Request Overview

This PR implements automated daily updates for SPDX license lists by detecting the latest release from the SPDX GitHub repository and creating pull requests with updated schemas when changes are detected.

Key Changes:

• Enhanced SpdxXsdGenerator to dynamically fetch the latest SPDX release version via GitHub API instead of using a hardcoded version
• Added GitHub Actions workflow for scheduled daily execution and manual triggering
• Modified update script to change to the correct directory before running Maven commands

Reviewed Changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 2 comments.

File	Description
.github/workflows/update_spdx_licenses.yml	New workflow that runs daily to check for SPDX updates, generate schemas, and create PRs when changes are detected
tools/src/main/java/org/cyclonedx/tools/SpdxXsdGenerator.java	Refactored to support dynamic version detection from GitHub API with configurable tag names and extracted schema generation into instance methods
tools/updateSpdx.sh	Added directory change to ensure Maven commands execute in the correct location

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