dragonfly GHA: need to ignore spelling

It depends on Rcpp, which fails to install.
We don't need the soft dependencies of fs, anyway,
but have no way of expression this currently.

.github/workflows/dragonflybsd.yaml

@@ -41,7 +41,7 @@ jobs:
           install-pandoc: false
           install-quarto: false
           cache-version: dragonflybsd-1
-          extra-packages: any::rcmdcheck, r-lib/fs, r-lib/openssl
+          extra-packages: any::rcmdcheck, r-lib/fs, r-lib/openssl, spelling=?ignore
           needs: check
 
       - uses: r-lib/actions/check-r-package@v2