docs: update localstack example for testcontainers-go (#1743)

Author: mdelapenya

content/en/user-guide/integrations/testcontainers/index.md

@@ -58,7 +58,7 @@ await localStackContainer.StartAsync()
     .ConfigureAwait(false);
 {{< /tab >}}
 {{< tab header="Go" lang="go">}}
-container, err := localstack.StartContainer(ctx, localstack.NoopOverrideContainerRequest)
+container, err := localstack.Run(ctx, "localstack/localstack:latest")
 {{< /tab >}}
 {{< tab header="Java" lang="java">}}
 LocalStackContainer localstack = new LocalStackContainer(DockerImageName.parse("localstack/localstack:3"));
@@ -77,42 +77,44 @@ config.ServiceURL = localStackContainer.GetConnectionString();
 using var client = new AmazonS3Client(config);
 {{< /tab >}}
 {{< tab header="Go" lang="go">}}
+type resolverV2 struct {
+    // you could inject additional application context here as well
+}
+
+func (*resolverV2) ResolveEndpoint(ctx context.Context, params s3.EndpointParameters) (smithyendpoints.Endpoint, error) {
+    // delegate back to the default v2 resolver otherwise
+    return s3.NewDefaultEndpointResolverV2().ResolveEndpoint(ctx, params)
+}
+
 func s3Client(ctx context.Context, l *localstack.LocalStackContainer) (*s3.Client, error) {
-    // the Testcontainers Docker provider is used to get the host of the Docker daemon
-    provider, err := testcontainers.NewDockerProvider()
+    mappedPort, err := l.MappedPort(ctx, nat.Port("4566/tcp"))
     if err != nil {
         return nil, err
     }
 
-    host, err := provider.DaemonHost(ctx)
+    provider, err := testcontainers.NewDockerProvider()
     if err != nil {
         return nil, err
     }
+    defer provider.Close()
 
-    mappedPort, err := l.MappedPort(ctx, nat.Port("4566/tcp"))
+    host, err := provider.DaemonHost(ctx)
     if err != nil {
         return nil, err
     }
 
-    customResolver := aws.EndpointResolverWithOptionsFunc(
-        func(service, region string, opts ...interface{}) (aws.Endpoint, error) {
-            return aws.Endpoint{
-                PartitionID:   "aws",
-                URL:           fmt.Sprintf("http://%s:%d", host, mappedPort.Int()),
-                SigningRegion: region,
-            }, nil
-        })
-
     awsCfg, err := config.LoadDefaultConfig(context.TODO(),
         config.WithRegion(region),
-        config.WithEndpointResolverWithOptions(customResolver),
         config.WithCredentialsProvider(credentials.NewStaticCredentialsProvider(accesskey, secretkey, token)),
     )
     if err != nil {
         return nil, err
     }
 
+    // reference: https://aws.github.io/aws-sdk-go-v2/docs/configuring-sdk/endpoints/#with-both
     client := s3.NewFromConfig(awsCfg, func(o *s3.Options) {
+        o.BaseEndpoint = aws.String("http://" + host + ":" + mappedPort.Port())
+        o.EndpointResolverV2 = &resolverV2{}
         o.UsePathStyle = true
     })