Upgrade kf_config.json to v2 (nested config + dtype)

kf_config.json

@@ -1,31 +1,35 @@
 {
   "library_name": "kerasformers",
-  "kerasformers_version": "1.1.3",
+  "kerasformers_version": "1.2.1",
   "model_module": "kerasformers.models.maxvit",
   "model_class": "MaxViTImageClassify",
   "variant": "maxvit_tiny_tf_384_in1k",
   "weights": "model.weights.h5",
+  "schema_version": 2,
+  "dtype": "float32",
   "model_type": "maxvit",
-  "stem_width": 64,
-  "depths": [
-    2,
-    2,
-    5,
-    2
-  ],
-  "embed_dim": [
-    64,
-    128,
-    256,
-    512
-  ],
-  "num_heads": [
-    2,
-    4,
-    8,
-    16
-  ],
-  "window_size": 12,
-  "image_size": 384,
-  "num_classes": 1000
+  "vision_config": {
+    "stem_width": 64,
+    "depths": [
+      2,
+      2,
+      5,
+      2
+    ],
+    "embed_dim": [
+      64,
+      128,
+      256,
+      512
+    ],
+    "num_heads": [
+      2,
+      4,
+      8,
+      16
+    ],
+    "window_size": 12,
+    "image_size": 384,
+    "num_classes": 1000
+  }
 }