Update golang to 1.12.0

Signed-off-by: ialidzhikov <[email protected]>

Author: ialidzhikov

cluster/addons/fluentd-elasticsearch/es-image/Dockerfile

@@ -12,7 +12,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-FROM golang:1.11.5 AS builder
+FROM golang:1.12.0 AS builder
 COPY elasticsearch_logging_discovery.go go.mod go.sum /
 RUN CGO_ENABLED=0 GOOS=linux GO111MODULE=on go build -a -ldflags "-w" -o /elasticsearch_logging_discovery /elasticsearch_logging_discovery.go