fix(ci): add pandoc, add publishing job

Author: machow

.github/workflows/ci.yml

@@ -83,6 +83,7 @@ jobs:
 
   publish-docs:
     name: "Publish Docs"
+    runs-on: ubuntu-latest
     needs: ["build-docs", "tests", "test-rsconnect"]
     steps:
       - uses: actions/download-artifact@v3