We currently emit array types as `List[T]` for Python, but `List[T]` is invariant, which causes type checkers like mypy to produce errors when values like `["foo", "bar"]` are passed as args typed as `List[pulumi.Input[str]]` (since `Input[str]` is an alias for `Union[T, Awaitable[T], Output[T]]`. To address this, we should move to using [`Sequence[T]`](https://docs.python.org/3/library/typing.html#typing.Sequence) which is covariant, and does not have this problem.
We actually already do this for `Dict` vs. `Mapping`, emitting map types as `Mapping[str, T]` rather than `Dict[str, T]` because `Mapping[str, T]` is covariant for the value. This change makes us consistent for array types.
These are the SDK changes necessary to support `Sequence[T]`.
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