Address GitHub Actions failing immediately for rcc

[d-hansen]

This PR addresses the issue of GitHub Actions failing immediately when running R-CMD-check.yaml (rcc):

Smoke test: stock R This request has been automatically failed because it uses a deprecated version of actions/upload-artifact: v2. Learn more: https://github.blog/changelog/2024-02-13-deprecation-notice-v1-and-v2-of-the-artifact-actions/

Turns out, the yaml script was using actions/upload-artifact@v2 to upload the smoke test SHA artifact. There is no reason not to just use the most recent version of the artifact uploader (v4) for this step.

[d-hansen]

Sorry I didn't dig deeper to why GitHub Actions was failing in my fork and address this pedantic little error last week (not that I introduced it - it was just that GitHub Actions actually followed through on deprecating v2 when they said they would).

[krlmlr]

Oh, a brownout? Thanks, good catch! I'm fixing elsewhere and propagate to this repo later.

[krlmlr]

Thanks again! This came in from elsewhere by now.