update notebooks

Author: Bruno Goncalves

1. Pitfalls.ipynb

@@ -5,7 +5,7 @@
    "metadata": {},
    "source": [
     "<div style=\"width: 100%; overflow: hidden;\">\n",
-    "    <div style=\"width: 150px; float: left;\"> <img src=\"data/D4Sci_logo_ball.png\" alt=\"Data For Science, Inc\" align=\"left\" border=\"0\"> </div>\n",
+    "    <div style=\"width: 150px; float: left;\"> <img src=\"https://raw.githubusercontent.com/DataForScience/Networks/master/data/D4Sci_logo_ball.png\" alt=\"Data For Science, Inc\" align=\"left\" border=\"0\" width=150px> </div>\n",
     "    <div style=\"float: left; margin-left: 10px;\"> <h1>Transforming Excel Analysis into pandas Data Models</h1>\n",
     "<h1>Excel Pitfalls</h1>\n",
     "        <p>Bruno Gonçalves<br/>\n",
@@ -52,26 +52,27 @@
      "name": "stdout",
      "output_type": "stream",
      "text": [
-      "watermark       2.0.2\n",
-      "matplotlib      3.1.3\n",
-      "pandas          1.0.1\n",
-      "numpy           1.18.1\n",
-      "autopep8        1.5\n",
-      "json            2.0.9\n",
-      "numpy_financial 1.0.0\n",
-      "Thu Sep 03 2020 \n",
+      "Python implementation: CPython\n",
+      "Python version       : 3.8.5\n",
+      "IPython version      : 7.19.0\n",
       "\n",
-      "CPython 3.7.3\n",
-      "IPython 6.2.1\n",
+      "Compiler    : Clang 10.0.0 \n",
+      "OS          : Darwin\n",
+      "Release     : 20.3.0\n",
+      "Machine     : x86_64\n",
+      "Processor   : i386\n",
+      "CPU cores   : 16\n",
+      "Architecture: 64bit\n",
       "\n",
-      "compiler   : Clang 4.0.1 (tags/RELEASE_401/final)\n",
-      "system     : Darwin\n",
-      "release    : 19.6.0\n",
-      "machine    : x86_64\n",
-      "processor  : i386\n",
-      "CPU cores  : 8\n",
-      "interpreter: 64bit\n",
-      "Git hash   : db6f805bfd2f0754fac849822010bc72ecbfeb20\n"
+      "Git hash: cf1f9e0456cec9d5d960512c3269cc904d79928a\n",
+      "\n",
+      "matplotlib     : 3.3.2\n",
+      "numpy          : 1.19.2\n",
+      "numpy_financial: 1.0.0\n",
+      "watermark      : 2.1.0\n",
+      "json           : 2.0.9\n",
+      "pandas         : 1.1.3\n",
+      "\n"
      ]
     }
    ],
@@ -1347,7 +1348,7 @@
    "name": "python",
    "nbconvert_exporter": "python",
    "pygments_lexer": "ipython3",
-   "version": "3.7.3"
+   "version": "3.8.5"
   },
   "toc": {
    "base_numbering": 1,