match padoc-version for install to 3.x

Author: schloerke

.github/workflows/apps-test-os.yml

@@ -27,7 +27,7 @@ on:
         required: false
       pandoc-version:
         type: string
-        default: "2.7.3"
+        default: "3.x"
         required: false
       packagemanager-cran-url:
         type: string