Update retinanet_presets.py (#2157)

* Update retinanet_presets.py

* nit

Author: sineeli

keras_hub/src/models/retinanet/retinanet_presets.py

@@ -11,6 +11,17 @@
             "params": 34121239,
             "path": "retinanet",
         },
-        "kaggle_handle": "kaggle://keras/retinanet/keras/retinanet_resnet50_fpn_coco/2",
-    }
+        "kaggle_handle": "kaggle://keras/retinanet/keras/retinanet_resnet50_fpn_coco/3",
+    },
+    "retinanet_resnet50_fpn_v2_coco": {
+        "metadata": {
+            "description": (
+                "RetinaNet model with ResNet50 backbone fine-tuned on COCO in "
+                "800x800 resolution with FPN features created from P5 level."
+            ),
+            "params": 31558592,
+            "path": "retinanet",
+        },
+        "kaggle_handle": "kaggle://keras/retinanet/keras/retinanet_resnet50_fpn_v2_coco/2",
+    },
 }