Update to golang 1.11.4 (elastic#9627)

```
go1.11.4 (released 2018/12/14) includes fixes to cgo, the compiler, linker, runtime, documentation, go command, and the net/http and go/types packages. It includes a fix to a bug introduced in Go 1.11.3 that broke go get for import path patterns containing "...". See the Go 1.11.4 milestone on our issue tracker for details.
```

more details at : https://github.com/golang/go/issues?q=milestone%3AGo1.11.4+label%3ACherryPickApproved

Dockerfile

@@ -1,4 +1,4 @@
-FROM golang:1.11.3
+FROM golang:1.11.4
 MAINTAINER Noémi Ványi <noemi.vanyi@elastic.co>
 
 RUN set -x && \