Center Title by default for px.imshow

[s2t2]

Issue:

Many chart-making functions such as px.line, px.scatter, px.bar center the title by default (desired), but the px.imshow function displays the title on the left margin instead (not desired).

import plotly.express as px

fig = px.imshow(mat, title="My Title")

Current Workaround:

fig.update_layout(title={'text': "My Title", 'x':0.485, 'xanchor': 'center'}) # manually center the title

Proposed Solution:

The px.imshow function should center the title by default.