Bug fix: Update time_series.ipynb

Running this notebook in Google Colab produces an error because the file being unzipped in a folder and previous code is unable to find it.

Author: nectostr

site/en/tutorials/structured_data/time_series.ipynb

@@ -158,7 +158,7 @@
       },
       "outputs": [],
       "source": [
-        "df = pd.read_csv(csv_path)\n",
+        "df = pd.read_csv(os.path.join(csv_path,"jena_climate_2009_2016.csv"))\n",
         "# Slice [start:stop:step], starting from index 5 take every 6th record.\n",
         "df = df[5::6]\n",
         "\n",