increase status_code check to >= 500

[jonathanfeng-scale]

Pull Request Summary

Description

We have seen customer reports of receiving a 503 response back from Scale while creating tasks. This seems like an error and the task did not successfully create, but actually the task creation was successful (it just took longer than our API gateway's limit or some similar issue).

In the past, this would return a 500 response, but now it also returns 503 so this change will also catch the 503.

How did you test your code?

Which of the following have you done to test your changes? Please describe the tests that you ran to verify your changes.

• Created new unit tests in tests/ for the newly implemented methods
• Updated existing unit tests in tests/ to cover changes made to existing methods

Checklist

Please make sure all items in this checklist have been fulfilled before sending your PR out for review!

• I have commented my code in details, particularly in hard-to-understand areas
• I have updated Readme.rst document with examples for newly implemented public methods
• I have reviewed Deployment and Publishing Guide for Python SDK document
• I incremented the SDK version in _version.py (unless this PR only updates the documentation).
• In order to release a new version, a "Release Summary" needs to be prepared and published after the merge