fix links

Author: LiamConnors

Diff for: doc/python/network-graphs.md

@@ -134,7 +134,7 @@ fig = go.Figure(data=[edge_trace, node_trace],
                 hovermode='closest',
                 margin=dict(b=20,l=5,r=5,t=40),
                 annotations=[ dict(
-                    text="Python code: <a href='https://plotly.com/ipython-notebooks/network-graphs/'> https://plotly.com/ipython-notebooks/network-graphs/</a>",
+                    text="Python code: <a href='https://plotly.com/python/v3/ipython-notebooks/network-graphs/'> https://plotly.com/python/v3/ipython-notebooks/network-graphs/</a>",
                     showarrow=False,
                     xref="paper", yref="paper",
                     x=0.005, y=-0.002 ) ],

Diff for: doc/python/peak-finding.md

@@ -36,7 +36,7 @@ jupyter:
 
 #### Imports
 
-The tutorial below imports [Pandas](https://plotly.com/pandas/intro-to-pandas-tutorial/), and [SciPy](https://www.scipy.org/).
+The tutorial below imports [Pandas](https://pandas.pydata.org/docs/user_guide/10min.html), and [SciPy](https://www.scipy.org/).
 
 ```python
 import pandas as pd

Diff for: doc/python/smoothing.md

@@ -36,7 +36,7 @@ jupyter:
 
 #### Imports
 
-The tutorial below imports [NumPy](http://www.numpy.org/), [Pandas](https://plotly.com/pandas/intro-to-pandas-tutorial/), [SciPy](https://www.scipy.org/) and [Plotly](https://plotly.com/python/getting-started/).
+The tutorial below imports [NumPy](http://www.numpy.org/), [Pandas](https://pandas.pydata.org/docs/user_guide/10min.html), [SciPy](https://www.scipy.org/) and [Plotly](https://plotly.com/python/getting-started/).
 
 ```python
 import plotly.graph_objects as go