chore: update readme

Readme.md

@@ -8,7 +8,6 @@ MailerLite Golang SDK
 
 - [Installation](#installation)
 - [Usage](#usage)
-    - [Testing](#testing)
     - [Subscribers](#subscribers)
         - [Get a list of subscribers](#get-a-list-of-subscribers)
         - [Get a single subscriber](#get-a-single-subscriber)
@@ -65,30 +64,6 @@ MailerLite Golang SDK
     - [Campaign languages](#languages)
         - [Get a list of languages](#get-a-list-of-languages)
 
-## Testing 
-We provide interfaces for all services to help with testing
-
-```go
-type mockSubscriberService struct {
-	mailerlite.SubscriberService
-}
-
-func (m *mockSubscriberService) List(ctx context.Context, options *mailerlite.ListSubscriberOptions) (*mailerlite.RootSubscribers, *mailerlite.Response, error) {
-	return &mailerlite.RootSubscribers{Data: []mailerlite.Subscriber{{Email: "[email protected]"}}}, nil, nil
-}
-
-func TestListSubscribers(t *testing.T) {
-	client := &mailerlite.Client{}
-	client.Subscriber = &mockSubscriberService{}
-
-	ctx := context.Background()
-	result, _, err := client.Subscriber.List(ctx, nil)
-	if err != nil || len(result.Data) == 0 || result.Data[0].Email != "[email protected]" {
-		t.Fatalf("mock failed")
-	}
-}
-```
-
 ## Subscribers
 
 ### Get a list of subscribers
@@ -1449,6 +1424,29 @@ func main() {
 
 # Testing
 
+We provide interfaces for all services to help with testing
+
+```go
+type mockSubscriberService struct {
+	mailerlite.SubscriberService
+}
+
+func (m *mockSubscriberService) List(ctx context.Context, options *mailerlite.ListSubscriberOptions) (*mailerlite.RootSubscribers, *mailerlite.Response, error) {
+	return &mailerlite.RootSubscribers{Data: []mailerlite.Subscriber{{Email: "[email protected]"}}}, nil, nil
+}
+
+func TestListSubscribers(t *testing.T) {
+	client := &mailerlite.Client{}
+	client.Subscriber = &mockSubscriberService{}
+
+	ctx := context.Background()
+	result, _, err := client.Subscriber.List(ctx, nil)
+	if err != nil || len(result.Data) == 0 || result.Data[0].Email != "[email protected]" {
+		t.Fatalf("mock failed")
+	}
+}
+```
+
 [pkg/testing](https://golang.org/pkg/testing/)
 
 ```