Kubernetes doesn't accept any other value but string in nodeSelector,
but if we specified ambiguous value like true, it's treated as a
non-string like bool and then failed to create resource because of type
mis-match, that's why we should make value of nodeSelector enclosed by
double quotations to ensure value is always string
**Problem:**
Schedule kubedns component to Windows node will cause DNS doesn't work
well
**Solution:**
Add nodeAffinity to kubedns
**Issue:**
https://github.com/rancher/rancher/issues/17423
