Doesn't seem to do anything at all?

**Describe the bug**
I've installed the extension and signed in to github, but nothing has changed in VS code. There's no sidebar icon like in the screenshots, and since there's no documentation, I have no idea what to do now.

**To Reproduce**
Steps to reproduce the behavior:
1. Install github actions extension
2. ???

**Expected behavior**
I actually have no idea what to expect. Is this supposed to let me run and debug github actions locally? I have no idea because there's no documentation. Selecting my workflow yml files just views them same as it always has.

I would at least expect to see something similar to in your screenshots, but it looks no different with it installed or not.

**Extension Version**
`v0.27.2`

ソースファイルやテストは指定されていません。まず拡張機能のインストールとアクティベーションの動作を確認し、次にサイドバーのアイコンと workflow ファイルがどう動作すべきかを文書化してください。新しいユーザーがインストール手順に従い、拡張機能の想定される動作を理解できれば完了です。

索引モデルが issue の本文から書いたものです。