fix pandas example

Author: LiamConnors

doc/python/pandas-backend.md

@@ -55,7 +55,7 @@ import pandas as pd
 pd.options.plotting.backend = "plotly"
 
 df = pd.DataFrame(dict(a=[1,3,2], b=[3,2,1]))
-fig = df.plot(title=dict(text="Pandas Backend Example"), template="simple_white",
+fig = df.plot(title="Pandas Backend Example", template="simple_white",
               labels=dict(index="time", value="money", variable="option"))
 fig.update_yaxes(tickprefix="$")
 fig.show()