Fix unhashable exception SDKError

[jpennors]

Hi 👋

A small PR for an issue I recently got with the SDKError exception class.

Context

To be monitored and processed, exceptions might be mapped as dictionary or set. I recently encounter the following issue using the mistral Python client and Rollbar :

TypeError("unhashable type: 'SDKError'")

This means, I got an exception using the mistral library and I'm not aware of it because the exception is not sent to Rollbar.

Bug reproduction

Just do :

error = SDKError("", 0, "")
print({error})

It will fail. Then add frozen=True like in the PR and it will work well.

Here is where an exception is mapped as a set in Rollbar : https://github.com/rollbar/pyrollbar/blob/84efba4ae3c9a5faef60b3bed3856f27940a0964/rollbar/__init__.py#L817

[GaspardBT]

Hey 👋
Thanks for opening this PR and the detailed reproduction, those files are auto generated and shouldn't be modified this way.
I will report this issue to our code generation partner to see how we can address this issue.

Could you open an issue with this bug report so we can keep you updated
Thanks