Merge pull request #64 from openwide-java/null-safe-fix

skip_confirmation should be null safe

src/main/java/org/gitlab/api/GitlabAPI.java

@@ -138,7 +138,7 @@ public class GitlabAPI {
 
         Query query = new Query()
                 .append("email", email)
-                .appendIf("confirm", !skip_confirmation)
+                .appendIf("confirm", skip_confirmation == null ? null : !skip_confirmation)
                 .appendIf("password", password)
                 .appendIf("username", username)
                 .appendIf("name", fullName)