Update links fr the Memcached go sample

The Memcached Go Sample was moved from the root to dir /go/Memcached as the others types. 
So, this PR, was done just to update the ref links.

Author: camilamacedo86

doc/sdk-cli-reference.md

@@ -517,7 +517,7 @@ The operator-sdk test command runs go tests built using the Operator SDK's test
 
 ```console
 $ operator-sdk test local ./test/e2e/
-ok    github.com/operator-framework/operator-sdk-samples/memcached-operator/test/e2e  20.410s
+ok    github.com/operator-framework/operator-sdk-samples/go/memcached-operator/test/e2e  20.410s
 ```
 
 ## up

doc/test-framework/writing-e2e-tests.md

@@ -65,8 +65,8 @@ sure to import `testing`, the operator-sdk test framework (`pkg/test`) as well a
 import (
     "testing"
 
-    cachev1alpha1 "github.com/operator-framework/operator-sdk-samples/memcached-operator/pkg/apis/cache/v1alpha1"
-    "github.com/operator-framework/operator-sdk-samples/memcached-operator/pkg/apis"
+    cachev1alpha1 "github.com/operator-framework/operator-sdk-samples/go/memcached-operator/pkg/apis/cache/v1alpha1"
+    "github.com/operator-framework/operator-sdk-samples/go/memcached-operator/pkg/apis"
 
     framework "github.com/operator-framework/operator-sdk/pkg/test"
 )
@@ -327,11 +327,11 @@ Since the CRD is not namespaced, it must be deleted separately. Clean up the CRD
 $ kubectl delete -f deploy/crds/cache.example.com_memcacheds_crd.yaml
 ```
 
-[memcached-sample]:https://github.com/operator-framework/operator-sdk-samples/tree/master/memcached-operator
+[memcached-sample]:https://github.com/operator-framework/operator-sdk-samples/tree/master/go/memcached-operator
 [framework-link]:https://github.com/operator-framework/operator-sdk/blob/master/pkg/test/framework.go
 [testctx-link]:https://github.com/operator-framework/operator-sdk/blob/master/pkg/test/context.go
 [e2eutil-link]:https://github.com/operator-framework/operator-sdk/tree/master/pkg/test/e2eutil
-[memcached-test-link]:https://github.com/operator-framework/operator-sdk-samples/blob/master/memcached-operator/test/e2e/memcached_test.go
+[memcached-test-link]:https://github.com/operator-framework/operator-sdk-samples/blob/master/go/memcached-operator/test/e2e/memcached_test.go
 [scheme-link]:https://github.com/operator-framework/operator-sdk/blob/master/pkg/test/framework.go#L109
 [sdk-cli-ref]:https://github.com/operator-framework/operator-sdk/blob/master/doc/sdk-cli-reference.md#test
 [main-entry-link]:https://github.com/operator-framework/operator-sdk/blob/master/pkg/test/main_entry.go#L25

doc/user/unit-testing.md

@@ -266,6 +266,6 @@ func TestMemcachedController(t *testing.T) {
 [doc-cr-fake-client]: https://godoc.org/github.com/kubernetes-sigs/controller-runtime/pkg/client/fake
 [repo-memcached-reconcile]: https://github.com/operator-framework/operator-sdk-samples/blob/4c6934448684a6953ece4d3d9f3f77494b1c125e/memcached-operator/pkg/controller/memcached/memcached_controller.go#L82
 [doc-reconcile]: https://godoc.org/sigs.k8s.io/controller-runtime/pkg/reconcile#Reconciler
-[code-test-example]: https://github.com/operator-framework/operator-sdk-samples/blob/master/memcached-operator/pkg/controller/memcached/memcached_controller_test.go#L25
+[code-test-example]: https://github.com/operator-framework/operator-sdk-samples/blob/master/go/memcached-operator/pkg/controller/memcached/memcached_controller_test.go#L25
 [user-guide]: ../user-guide.md#register-with-the-managers-scheme
 [ocp-doc-v1-route]: https://docs.openshift.com/container-platform/3.11/rest_api/apis-route.openshift.io/v1.Route.html