update segment training (#57)

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Co-authored-by: ayush chaurasia <ayush.chaurarsia@gmail.com>

ultralytics/yolo/v8/classify/val.py

@@ -23,3 +23,7 @@ class ClassificationValidator(BaseValidator):
         acc = torch.stack((self.correct[:, 0], self.correct.max(1).values), dim=1)  # (top1, top5) accuracy
         top1, top5 = acc.mean(0).tolist()
         return {"top1": top1, "top5": top5, "fitness": top5}
+
+    @property
+    def metric_keys(self):
+        return ["top1", "top5"]