update template

add a link to Bloom's taxonomy

contributing/notebook_template/notebook_template.ipynb

@@ -8,7 +8,7 @@
     "# Tutorial Title\n",
     "***\n",
     "## Learning Goals\n",
-    "Write three to five learning goals. A learning goal should describe what a reader should know or be able to do by the end of the tutorial that they didn't know or couldn't do before:\n",
+    "Write three to five learning goals using [Bloom's taxonomy](https://tips.uark.edu/using-blooms-taxonomy/) as a guide:\n",
     "\n",
     "```\n",
     "By the end of this tutorial, you will:\n",