Impose an upper limit on the polars dependency for functime version 0.9.5

[thomashusken]

Describe the bug
Version 0.9.5 of functime has no upper limit on the polars dependency so by default the latest version of polars will be installed (1.4.1 at the time of writing). I see that there is an issue already to make functime compatible with polars > 1.0, but the current behaviour means that the latest installation is broken.

To Reproduce
Steps to reproduce the behavior:

1. Create a clean Python environment (I use 3.10.7)
2. pip install functime
3. python -c 'import functime'
4. ModuleNotFoundError: No module named 'polars.utils.

Expected behavior
For the time being, imposing an upper limit on the polars version (I'm not sure what the latest compatible version is).

Desktop (please complete the following information):

• OS: Ubuntu 22.04
• Version: Python 3.10.7, functime 0.9.5, polars 1.4.1