Changed default `AutoDateLocator` kwarg ``interval_multiples`` to ``True``

The default value of the tick locator for dates, `.dates.AutoDateLocator`

kwarg ``interval_multiples`` was set to ``False`` which leads to not-nice

looking automatic ticks in many instances. The much nicer

``interval_multiples=True`` is the new default. See below to get the

old behavior back:

.. plot::

import matplotlib.pyplot as plt

import datetime

import matplotlib.dates as mdates

t0 = datetime.datetime(2009, 8, 20, 1, 10, 12)

tf = datetime.datetime(2009, 8, 20, 1, 42, 11)

fig, axs = plt.subplots(1, 2, constrained_layout=True)

ax = axs[0]

ax.axhspan(t0, tf, facecolor="blue", alpha=0.25)

ax.set_ylim(t0 - datetime.timedelta(minutes=3),

tf + datetime.timedelta(minutes=3))

ax.set_title('NEW DEFAULT')

ax = axs[1]

ax.axhspan(t0, tf, facecolor="blue", alpha=0.25)

ax.set_ylim(t0 - datetime.timedelta(minutes=3),

tf + datetime.timedelta(minutes=3))

# old behavior

locator = mdates.AutoDateLocator(interval_multiples=False, )

ax.yaxis.set_major_locator(locator)

ax.yaxis.set_major_formatter(mdates.AutoDateFormatter(locator))

ax.set_title('OLD')

plt.show()