[Feature Request] Default selection of "today" for date pickers

Allow users to default select today in the datepicker. For now, it's manual in Python:

from dash import Dash, dcc
from datetime import date

app = Dash(__name__)

app.layout = dcc.DatePickerSingle(
    id='date-picker',
    date=date.today()
)

if __name__ == '__main__':
    app.run(

For a DatePickerRange:

dcc.DatePickerRange(
    id='date-range',
    start_date=date.today(),
    end_date=date.today()
)

It would be handy to have a built-in option for this selection.