Update Panel logo (#4)

Author: ianthomas23

notebooks/14_next_steps.ipynb

@@ -132,7 +132,7 @@
     "#### Panel\n",
     "\n",
     "<a href=\"https://panel.holoviz.org/\" target=\"_blank\">\n",
-    "    <img src=\"https://panel.holoviz.org/_images/logo_stacked.png\" alt=\"Panel logo\" style=\"height: 75px;\">\n",
+    "    <img src=\"https://panel.holoviz.org/_images/logo_horizontal_light_theme.png\" alt=\"Panel logo\" style=\"height: 75px;\">\n",
     "</a>\n",
     "\n",
     "[Panel](https://panel.holoviz.org/) is a Python library for building interactive\n",