ci: dispatch mitreattack-python release info updates

[scotluns]

Why

This adds the release-side trigger for keeping mitreattack-python metadata current after ATT&CK STIX 2.1 releases are published from attack-stix-data.

What Changed

• Adds a release: published workflow that parses the ATT&CK version from the v* release tag
• Uses the ATTACK_AUTOBOT GitHub App token to dispatch the matching workflow in mitreattack-python
• Keeps a manual workflow_dispatch path so the dispatch can be retried for a specific version

Relationship

Companion to mitre-attack/mitreattack-python#242. This PR dispatches the workflow added there when an attack-stix-data release is published; that companion workflow validates both STIX release sources through the updater and creates the actual mitreattack-python metadata PR.

How To Verify

• Ruby YAML parse check passed locally for .github/workflows/dispatch-mitreattack-python-release-info.yml

Known Gaps

• actionlint is not installed locally, so GitHub Actions semantic linting was not run.