Using devcontainer in GitHub Actions

[matheusmoreira]

I recently merged a fix for the devcontainer, it should be good for years. There's a possible improvement though: using GitHub Actions to test the devcontainer by automatically building the project inside it. I'm creating this issue to track progress towards that goal.

References:

• PR Update Devcontainer Dockerfile #442
• https://github.com/devcontainers/ci/blob/main/docs/github-action.md
• https://github.com/nlordell/features/blob/149739fb619719cedec3249b290f8d9dc9b4ab0c/.github/workflows/release.yaml#L16-L24