r is installed by default on GHA

.github/actions/pre-test/action.yml

@@ -20,7 +20,6 @@ runs:
       echo 'C:\Strawberry\c\bin' >> "$GITHUB_PATH"
 
       testing/get-dart.sh
-      pwsh testing/get-r.ps1
   - name: setup (linux)
     shell: bash
     if: runner.os == 'Linux'
@@ -31,8 +30,7 @@ runs:
       sudo apt-get install -y --no-install-recommends \
         lua5.3 \
         liblua5.3-dev \
-        luarocks \
-        r-base
+        luarocks
 
       testing/get-coursier.sh
       testing/get-dart.sh