Add IRkernel (R) to CI matrix

Tests the R kernel using IRkernel package.

Author: rgbkrk

.github/workflows/conformance.yml

@@ -30,6 +30,11 @@ jobs:
               echo "$HOME/.deno/bin" >> $GITHUB_PATH
               $HOME/.deno/bin/deno jupyter --install
             kernel-name: deno
+          - name: irkernel
+            install: |
+              Rscript -e "install.packages('IRkernel', repos='https://cloud.r-project.org')"
+              Rscript -e "IRkernel::installspec()"
+            kernel-name: ir
 
     steps:
       - uses: actions/checkout@v4
@@ -43,6 +48,12 @@ jobs:
         with:
           python-version: "3.12"
 
+      - name: Set up R
+        if: matrix.kernel.name == 'irkernel'
+        uses: r-lib/actions/setup-r@v2
+        with:
+          r-version: "4.3"
+
       - name: Cache cargo
         uses: actions/cache@v4
         with: