[BUG] Setting a float into an int dtype series through iloc should cast the series

[brandon-b-miller]

Describe the bug
Setting a float into a pandas series of int dtype should cast the series to float, but what happens now is the incoming scalar gets rounded and the series remains int dtype.

Steps/Code to reproduce bug

>>> psr = pd.Series([1,2,3])
>>> gsr = cudf.Series([1,2,3])
>>> psr
0    1
1    2
2    3
dtype: int64
>>> gsr
0    1
1    2
2    3
dtype: int64
>>> psr.iloc[1] = 0.5
>>> gsr.iloc[1] = 0.5
>>> psr
0    1.0
1    0.5
2    3.0
dtype: float64
>>> gsr
0    1
1    0
2    3
dtype: int64

Expected behavior
We should get the same thing as pandas here.

Environment overview (please complete the following information)
22.02

Environment details
Please run and paste the output of the cudf/print_env.sh script here, to gather any other relevant environment details

Additional context
Came up during #8693

[github-actions]

This issue has been labeled inactive-30d due to no recent activity in the past 30 days. Please close this issue if no further response or action is needed. Otherwise, please respond with a comment indicating any updates or changes to the original issue and/or confirm this issue still needs to be addressed. This issue will be labeled inactive-90d if there is no activity in the next 60 days.

[github-actions]

This issue has been labeled inactive-90d due to no recent activity in the past 90 days. Please close this issue if no further response or action is needed. Otherwise, please respond with a comment indicating any updates or changes to the original issue and/or confirm this issue still needs to be addressed.

[wence-]

Fixed by #12074