Remove **kwargs from plot.timeseries()

timeseries() is a convenience function — kwargs were only forwarded
to plotly's update_layout and silently ignored for matplotlib.

Update README and notebook to use fig.update_layout() directly.

Closes #463

Author: ecomodeller

README.md

@@ -103,7 +103,8 @@ cc.plot.scatter()
 Timeseries plots can either be static and report-friendly ([matplotlib](https://matplotlib.org/)) or interactive with zoom functionality ([plotly](https://plotly.com/python/)).
 
 ```python
-cc["HKNA"].plot.timeseries(width=1000, backend="plotly")
+fig = cc["HKNA"].plot.timeseries(backend="plotly")
+fig.update_layout(width=1000)
 ```
 
 ![timeseries](https://raw.githubusercontent.com/DHI/modelskill/main/images/plotly_timeseries.png)