Anonymous should be an object in the builder as well

Author: jkodumal

src/main/java/com/launchdarkly/client/LDUser.java

@@ -113,7 +113,7 @@ public static class Builder {
     private String email;
     private String name;
     private String avatar;
-    private boolean anonymous;
+    private Boolean anonymous;
     private LDCountryCode country;
     private Map<String, JsonElement> custom;