Keras: Update Wandb imports and model checkpoint file extension (#614)

Author: ngrayluna

colabs/intro/Intro_to_Weights_&_Biases_keras.ipynb

@@ -160,7 +160,7 @@
     "import random\n",
     "import numpy as np\n",
     "import tensorflow as tf\n",
-    "from wandb.keras import WandbMetricsLogger, WandbModelCheckpoint\n",
+    "from wandb.integration.keras import WandbMetricsLogger, WandbModelCheckpoint\n",
     "\n",
     "# Simple Keras Model\n",
     "\n",
@@ -209,7 +209,7 @@
     "    # Add WandbMetricsLogger to log metrics and WandbModelCheckpoint to log model checkpoints\n",
     "    wandb_callbacks = [\n",
     "        WandbMetricsLogger(),\n",
-    "        WandbModelCheckpoint(filepath=\"my_model_{epoch:02d}\"),\n",
+    "        WandbModelCheckpoint(filepath=\"my_model_{epoch:02d}.keras\"),\n",
     "    ]\n",
     "\n",
     "    model.fit(\n",