add mean to plotly histogram code example

Example 1: histogram chart plotly

import plotly.express as px
df = px.data.tips()
fig = px.histogram(df, x="total_bill", nbins=20)
fig.show()

Example 2: histogram chart plotly

import plotly.express as px
import numpy as np

df = px.data.tips()
# create the bins
counts, bins = np.histogram(df.total_bill, bins=range(0, 60, 5))
bins = 0.5 * (bins[:-1] + bins[1:])

fig = px.bar(x=bins, y=counts, labels={'x':'total_bill', 'y':'count'})
fig.show()