Switch to_timedelta argument type from list to Sequence

[headtr1ck]

Describe the bug
to_timedelta uses a list of a union argument type.
This will raise false positive errors when passing a list of a single type because list is invariant.

To Reproduce

import pandas as pd

pd.to_timedelta(["1 day"])

produces:

error: Argument 1 to "to_timedelta" has incompatible type "list[str]"; expected "Union[Sequence[Union[float, timedelta]], list[Union[str, float, timedelta]], tuple[Union[str, float, timedelta], ...], range, Union[ExtensionArray, ndarray[Any, Any]], Index[Any]]" [arg-type]
note: "List" is invariant -- see https://mypy.readthedocs.io/en/stable/common_issues.html#variance
note: Consider using "Sequence" instead, which is covariant

Please complete the following information:

• OS: Win
• OS Version 10
• python 3.9.7
• version of type checker mypy 1.8.0
• version of installed pandas-stubs 2.2.2.240603

[Dr-Irv]

Thanks for the report. I agree - we can change list to Sequence at

pandas-stubs/pandas-stubs/core/tools/timedeltas.pyi

Line 35 in 9d5348e

| list[str | float | timedelta]

PR with test welcome.