Ensure GitHub actions workflow exists and is correct

[MelSumner]

Summary

Per the plan to make this org's add-ons more consistent so it is simpler for org volunteers to maintain, we want to make sure each repo has a .github/workflows/ci.yml file.

Outcome

This repo should have a GitHub Actions file that is as aligned with the rest of the addons in this org as much as is sensible.

Acceptance Criteria

This issue is considered complete when:

• Look to see if there is a GitHub actions workflow file (.github/workflows/ci.yml)
• If it is not there, add it
• if it is inconsistently placed or named, fix that
• ensure no other CI is being used in the add-on (especially outdated ones)

Questions? Ask in the #adopted-ember-addons channel in Discord.