Update demo_linearboost_usage.ipynb

Author: hamidkm9

notebooks/demo_linearboost_usage.ipynb

@@ -154,7 +154,6 @@
    ],
    "source": [
     "import optuna\n",
-    "import pandas as pd\n",
     "import numpy as np\n",
     "from sklearn.model_selection import StratifiedKFold, cross_val_score\n",
     "\n",