title: Validation groups extending Default not being validated by default
body: <p>I have the following validation groups:</p>
  
  <pre><code>public class ValidationGroups {
  
      public interface Create extends Default {}
  
      public interface Update extends Default {}
  
  }
  </code></pre>
  
  <p>And my annotated entity:</p>
  
  <pre><code>public class Usuario implements UserDetails {
  
      @NotNull(groups = { Update.class })
      @NotBlank(groups = { Update.class })
      @Length(max = 255, groups = { Update.class })
      private String name;
  
      @NotNull @NotEmpty @Email
      private String email;
  
  }
  </code></pre>
  
  <p>But when I try to validate my entity using the default validation the field <code>name</code> isn't validated at all, even when it's group explicitly extends <code>Default</code> (annotating with <code>@Valid</code> would do the same):</p>
  
  <pre><code>@PostMapping("signup")
  public String createUser(@Validated User user, 
              BindingResult result, Model model, RedirectAttributes redirectAttributes) {
  </code></pre>
  
  <p>The only way I can get all fields validated is by explicitly adding the Default group in the @Validated annotation like this:</p>
  
  <pre><code>@PostMapping("signup")
  public String createUser(@Validated({ Default.class, Update.class }) User user, 
              BindingResult result, Model model, RedirectAttributes redirectAttributes) {
  </code></pre>
  
  <p>Shouldn't by default all fields annotated with groups extending <code>Default</code> be validated when no groups are specified?</p>