Migrate to non-deprecated DynamoDB endpoint setup

The per-AWS-client endpoint configuration is deprecated in favor of
specifying this on individual service clients.

Author: ahamlinman

internal/store/dynamodb/factory.go

@@ -5,7 +5,6 @@ import (
 	"os"
 
 	"github.com/aws/aws-sdk-go-v2/aws"
-	"github.com/aws/aws-sdk-go-v2/config"
 	"github.com/aws/aws-sdk-go-v2/service/dynamodb"
 
 	"github.com/ahamlinman/randomizer/internal/awsconfig"
@@ -18,13 +17,17 @@ import (
 // AWS configuration is read as described at
 // https://docs.aws.amazon.com/cli/latest/userguide/cli-chap-getting-started.html.
 func FactoryFromEnv(ctx context.Context) (func(string) randomizer.Store, error) {
-	cfg, err := awsConfigFromEnv(ctx)
+	cfg, err := awsconfig.New(ctx)
 	if err != nil {
 		return nil, err
 	}
 
-	db := dynamodb.NewFromConfig(cfg)
 	table := tableFromEnv()
+	db := dynamodb.NewFromConfig(cfg, func(opts *dynamodb.Options) {
+		if endpoint := os.Getenv("DYNAMODB_ENDPOINT"); endpoint != "" {
+			opts.BaseEndpoint = aws.String(endpoint)
+		}
+	})
 
 	return func(partition string) randomizer.Store {
 		store, err := New(db, table, partition)
@@ -35,21 +38,6 @@ func FactoryFromEnv(ctx context.Context) (func(string) randomizer.Store, error)
 	}, nil
 }
 
-func awsConfigFromEnv(ctx context.Context) (aws.Config, error) {
-	var extraOptions []awsconfig.Option
-	if endpoint := os.Getenv("DYNAMODB_ENDPOINT"); endpoint != "" {
-		extraOptions = append(extraOptions,
-			config.WithEndpointResolverWithOptions(aws.EndpointResolverWithOptionsFunc(
-				func(_, _ string, _ ...any) (aws.Endpoint, error) {
-					return aws.Endpoint{URL: endpoint}, nil
-				},
-			)),
-		)
-	}
-
-	return awsconfig.New(ctx, extraOptions...)
-}
-
 func tableFromEnv() string {
 	if table := os.Getenv("DYNAMODB_TABLE"); table != "" {
 		return table