add cran check workflow

.github/workflows/cran-checks.yaml

@@ -0,0 +1,18 @@
+name: Check CRAN status
+
+on:
+  schedule:
+    # Runs daily at 4:00 PM UTC (9:00 AM PST)
+    - cron: '0 16 * * *'  
+  # allows for manually running of the check
+  workflow_dispatch:
+
+jobs:
+  check_cran_status:
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Get CRAN checks
+        uses: flrsh-dev/cran-checks/check-pkg
+        with:
+          pkg: b64