rr.save not accepting pathlib.Path

[roym899]

rr.save is only accepting strings currently, it would be nice to support pathlib.Path objects directly.

To Reproduce

import rerun as rr
import pathlib
rr.init("test")
rr.save(pathlib.Path("./test.rrd"))

gives

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File ".../lib/python3.10/site-packages/rerun_sdk/rerun/sinks.py", line 67, in save
    bindings.save(path=path, recording=recording)
TypeError: argument 'path': 'PosixPath' object cannot be converted to 'PyString'

Rerun version

rerun_py 0.9.1 [rustc 1.72.1 (d5c2e9c34 2023-09-13), LLVM 16.0.5] x86_64-unknown-linux-gnu 00fa796, built 2023-10-12T12:13:35Z