Is your feature request related to a problem? Please describe.

When using the https://marketplace.visualstudio.com/items?itemName=GitHub.vscode-github-actions extension and editing GitHub workflows files, Deno isn't formatting the yml files because the extension has its own language github-actions-workflow.

Describe the solution you'd like

Include the "github-actions-workflow" as a target language to format, similar to this PR: https://github.com/bluebrown/vscode-extension-yamlfmt/pull/9/files