Fix a typo
Fix a typo

Follow up #588

README.md.erb should be updated.

Signed-off-by: Kentaro Hayashi <f80b60a638b9855e938d3bbb8dcd3c74d400b0aa@clear-code.com>

fluent/fluentd-kubernetes-daemonset,fluent/fluentd-kubernetes-daemonset,fluent/fluentd-kubernetes-daemonset