Added index column name after resample (issue #3827)

[eric-bonfadini]

This fixes #3827
Fixes #3660

I added the test mentioned in the issue in dask/dataframe/tseries/tests/test_resample.py

• Tests added / passed
• Passes flake8 dask

[TomAugspurger]

Does this also close #3660?

[eric-bonfadini]

@TomAugspurger yes, I ran both the snippets reported in that issue without errors.
Thanks for pointing out!

print(ddf2.compute().resample('1min').mean())
                        data1     data2
time                                   
1980-01-01 00:00:00  0.093619  0.006039
1980-01-01 00:01:00 -1.698607  0.146224
1980-01-01 00:02:00  0.603537  0.514630
1980-01-01 00:03:00 -1.207392  0.161776
1980-01-01 00:04:00 -1.089236 -0.329725
...

print(ddf2.resample('1min').mean().compute())
                        data1     data2
time                                   
1980-01-01 00:00:00  0.093619  0.006039
1980-01-01 00:01:00 -1.698607  0.146224
1980-01-01 00:02:00  0.603537  0.514630
1980-01-01 00:03:00 -1.207392  0.161776
1980-01-01 00:04:00 -1.089236 -0.329725
...

[TomAugspurger]

Ok, thanks!