ci: upgrade r version

Author: sgratzl

.github/workflows/ci.yml

@@ -13,7 +13,7 @@ jobs:
       - uses: actions/setup-node@v3
       - uses: r-lib/actions/setup-r@v1
         with:
-          r-version: 3.6
+          r-version: 4.2
       - uses: r-lib/actions/setup-pandoc@v1
       - name: Cache R packages
         uses: actions/cache@v2