feat: Show latest version of action in hover tooltip

[ZiuChen]

Closes#326

Summary

When hovering over a uses: directive in workflow files, the extension now shows the latest available version of the referenced action alongside the existing language server hover (action name + description).

If the current version is outdated, a Quick Fix code action is available to update the version in-place.

How it works

VS Code natively merges hover results from multiple providers. The language server continues to provide action name, description, and link — our new provider adds version information below it, separated by a divider.

Screenshots

Hover tooltip showing latest version:

Quick Fix code action:

Testing

1. Open a project with .github/workflows/ files
2. Hover over any uses: owner/repo@ref line → see latest version in tooltip
3. Place cursor on an outdated action → press Cmd+. → select update action

[Copilot]

Pull request overview

Adds editor UX for GitHub Actions uses: references by showing the latest available version on hover and offering a Quick Fix to update outdated refs.

Changes:

• Introduces a hover provider that looks up and displays the latest action version from GitHub.
• Introduces a Quick Fix code action to update @ref to the latest tag (and optionally latest major tag).
• Registers the new hover + code action providers for workflow/action YAML documents during extension activation.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 10 comments.

File	Description
src/hover/actionVersionHoverProvider.ts	New hover provider that parses uses: lines and fetches latest version via GitHub API with caching.
src/hover/actionVersionCodeActionProvider.ts	New Quick Fix provider that offers in-place ref updates based on fetched latest version info.
src/extension.ts	Registers the new hover and code action providers for workflow/action document selectors.

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.