API: Revert changes to describe
https://github.com/pandas-dev/pandas/pull/30209/ has some changes to describe for datelike data. I think the changes count as API breaking and should wait until a 2.0, possibly with a deprecation warning.

cc @david-cortes, @jreback.

master:

```python
In [1]: import pandas as pd

In [2]: pd.Series(pd.date_range('2000', periods=10)).describe()
Out[2]:
count                     10
mean     2000-01-05 12:00:00
min      2000-01-01 00:00:00
25%      2000-01-03 06:00:00
50%      2000-01-05 12:00:00
75%      2000-01-07 18:00:00
max      2000-01-10 00:00:00
dtype: object

In [3]: pd.__version__
Out[3]: '1.1.0.dev0+1417.g12c9c626d'
```

1.0.2:

```python
In [1]: import pandas as pd

In [2]: pd.Series(pd.date_range('2000', periods=10)).describe()
Out[2]:
count                      10
unique                     10
top       2000-01-08 00:00:00
freq                        1
first     2000-01-01 00:00:00
last      2000-01-10 00:00:00
dtype: object

In [3]: pd.__version__
Out[3]: '1.0.2'
```


