chore(deps): update copilot skills

[github-actions]

Automated update of Copilot skills to their latest versions.

Updated files under plugins:

All skills are up to date.
All skills are up to date.
All skills are up to date.
1 update(s) available:
  • skills/gh-stack (github/gh-stack) f900e01d > f11c787b [v0.0.2]
Updated skills/gh-stack
All skills are up to date.
All skills are up to date.

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[Copilot]

Pull request overview

This PR is intended to update the gh-stack Copilot skill to the latest upstream version (v0.0.2) in the plugins/github plugin.

Changes:

• Adds a new SKILL.md for gh-stack containing updated upstream content and metadata (refs/tags/v0.0.2).
• Introduces a new skill file location under plugins/github/gh-stack/.

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[Copilot]

This skill file is placed at plugins/github/gh-stack/SKILL.md, but skill discovery/validation only looks for SKILL.md at plugins/<plugin>/skills/<skill>/SKILL.md (depth 4). As a result, this new file will not be discovered or validated, and the existing plugins/github/skills/gh-stack/SKILL.md remains on v0.0.1. Move/update the skill under plugins/github/skills/gh-stack/ (or update discovery/plugin layout consistently) to make the v0.0.2 update effective.