ci/docker: Add !operator/option into Dockerfile.dockerignore
ci/docker: Add !operator/option into Dockerfile.dockerignore

This commit is to exclude operator/option directory in
Dockerfile.dockerignore file to fix below issue

```
../pkg/aws/endpoints/resolver.go:18:2: cannot find package "." in:
12 9.053       /go/src/github.com/cilium/cilium/operator/option
```

Signed-off-by: Tam Mach <928487046a9c42ed56ed508a413e2eaabffae612@yahoo.com>

tklauser/cilium,tgraf/cilium,cilium/cilium,cilium/cilium,tgraf/cilium,tklauser/cilium,tgraf/cilium,cilium/cilium,michi-covalent/cilium,michi-covalent/cilium,tgraf/cilium,tgraf/cilium,cilium/cilium,tklauser/cilium,michi-covalent/cilium,michi-covalent/cilium,cilium/cilium,michi-covalent/cilium,tklauser/cilium,tklauser/cilium,tgraf/cilium