BUG: fix segfault on giving incorrect type to read_info layer

[m-richards]

This was user error, I was trying to do more or less this

layers = pyogrio.list_layers(...)
infos = [pyogrio.read_info(file, layer) for layer in layers]

forgetting that layers doesn't return a list of strings.

Here's a minimal reproducer:

import pyogrio
import geodatasets
pyogrio.read_info(geodatasets.get_path("nybb"), layer=['test']) # segfaults because layer is not a str

Still think it's worth this giving a proper error message though.

[theroggy]

Nice catch!

Just a small indentation suggestion...

[brendan-ward]

Thanks @m-richards ! Can you please add a changelog entry for 0.12? (merge from main first)