Worksheet.cell allows non-integer values

[hudcap]

The cell stub is defined as:

def cell(
    self, row: int, column: int, value: Optional[int] = ...
) -> Union[MergedCell, ReadOnlyCell, Cell]: ...

But the value parameter can be a float, string , time, etc. The docstring for cell has the following:

:param value: value of the cell (e.g. 5)
:type value: numeric or time or string or bool or none

Will make a PR, although I'm somewhat new to this whole type hinting.