Add `target` parameter to `pipe_input`

[elijahbenizzy]

Is your feature request related to a problem? Please describe.
Currently it assumes the first parameter. But that's a bit silly, we should use a target parameter. That would also allow pipe_input to work with other decorators cleanly.

Describe the solution you'd like

@pipe_input(
    step(...),
    step(...),
    target="b" # applies to parameter `b`
)
def foo(a: int, b: int) -> int:
    ...

Describe alternatives you've considered
Not doing this or just reordering parameters for the user.

Additional context
Tangentially related to this: #1160

[zilto]

Nitpick: should it be target or target_. Both are present in the codebase (from_.parquet(..., target="raw_data"), @tag(..., target_="field_b"))

[elijahbenizzy]

Nitpick: should it be target or target_. Both are present in the codebase (from_.parquet(..., target="raw_data"), @tag(..., target_="field_b"))

We use target_ for anything tag-related. E.G. with **kwargs so we don't hit namespacing issues with arbitrary tags (which could be called target). In this case it's not **kwargs, so I think target is correct.