New workflow to check tiltIndicator on PRs

[maurolepore]

The goal of this PR is to check tiltIndicator with changes in tiltToyData. It adds a workflow that runs on GitHub Actions. It runs R CMD check on tiltIndicator with the PR-version of tiltToyData.

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TODO

• [x] Link related issue/PR.
• [x] Describe the goal of the PR. Avoid details that are clear in the diff.
• [x] Mark the PR as draft.
• [ ] Include a unit test.
• [ ] Review your own PR in "Files changed".
• [ ] Ensure the PR branch is updated.
• [ ] Ensure the checks pass.
• [ ] Change the status from draft to ready.
• [ ] Polish the PR title and description.
• [ ] Assign a reviewer.

EXCEPTIONS

• [ ] Slide here any item that you intentionally choose to not do.