Packages not saved to cache in `setup-renv` when using pak

[Bisaloo]

Describe the bug

Since I have switched to pak in my setup-renv, it looks like all packages (excepted pak itself) are reinstalled for each run instead of being cached:

      - uses: r-lib/actions/setup-renv@v2
+       env:
+         RENV_CONFIG_PAK_ENABLED: "true"

To Reproduce

https://github.com/r-hub/cransays/actions/runs/27604973809/job/81614615594

Expected behavior

Before the switch to pak: https://github.com/r-hub/cransays/actions/runs/27491524574/job/81257498288

[Bisaloo]

I'll look into it more but one potential direction to explore is that when using pak, renv might not respect the RENV_PATHS_ROOT var set in

actions/setup-renv/action.yaml

Line 28 in d3c5be5

echo "RENV_PATHS_ROOT=${{ runner.temp }}/renv" >> $GITHUB_ENV

In the logs since pak has been enabled, I see:

These packages will be installed into "~/.cache/R/renv/library/cransays-4f3313d6/R-4.3/x86_64-pc-linux-gnu".