fluentd-daemonset-elasticsearch: Adopt k8s 1.16 API
fluentd-daemonset-elasticsearch: Adopt k8s 1.16 API

k8s 1.16 API request to specify selector.

Signed-off-by: Hiroshi Hatake <a476a6e5b5893650242fbf0b2961500a9bd9032e@clear-code.com>

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