fix for python 3.9 import crewai error [#215]

[lugq1990]

This is used to fix for the python 1.10 lower version to use crewai error with:

TypeError: unsupported operand type(s) for |: 'type' and 'NoneType' in rpm_controller.py 

With the change from | to Union type just alike: max_rpm: Union[int, None] = Field(default=None) attr.

[lugq1990]

@joaomdmoura could you please have a look for this? related to the lower python support from the type checking. Just keep consistency for the code side

[theCyberTech]

You should to use Python 3.10 or higher 3.9 is not supported, what is the reason you would need to use 3.9?

Doesn't make sense to try and fix this in my opinion?

[lugq1990]

You should to use Python 3.10 or higher 3.9 is not supported, what is the reason you would need to use 3.9?

Doesn't make sense to try and fix this in my opinion?

For me, currently base python version is 3.9, as for the framework side shouldn't just support with over 3.10, right?

[theCyberTech]

So two options,

1. Upgrade your base version to 3.10+
2. Run your crew in a virtual env using pyenv, poetry or conda

[theCyberTech]

https://docs.crewai.com/how-to/Installing-CrewAI/

This link states the Python versions CrewAI supports

[lugq1990]

Sure as the document mentions that support with python 3.10 over, than just close this pr