chore: switch to AWS SDK v2

cmd/service/service_test.go

@@ -20,9 +20,9 @@ func TestMainFunc_Success(t *testing.T) {
 
 func TestMainFunc_Invalid_AWS_Config(t *testing.T) {
 	os.Args = []string{"s3uploader", "--port", "7777", "--bucket", "test-bucket-somewhere", "--return-url", "https://example.org"}
-	_ = os.Setenv("AWS_STS_REGIONAL_ENDPOINTS", "unknown_value")
+	_ = os.Setenv("AWS_MAX_ATTEMPTS", "invalid")
 	defer func() {
-		_ = os.Unsetenv("AWS_STS_REGIONAL_ENDPOINTS")
+		_ = os.Unsetenv("AWS_MAX_ATTEMPTS")
 	}()
 	main()
 }