Update Segment dependency to segment-analytics-python from analytics-python

[dan-blanchard]

Describe changes

analytics-python was renamed to segment-analytics-python in 2021, so this PR switches to using the newer name for the package to ensure users get the newer version and the bugfixes it has.

Pre-requisites

Please ensure you have done the following:

• [x] I have read the CONTRIBUTING.md document.
• [x] I have based my new branch on develop and the open PR is targeting develop. If your branch wasn't based on develop read Contribution guide on rebasing branch to develop.

Types of changes

• [x] Bug fix (non-breaking change which fixes an issue)
• [ ] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to change)
• [ ] Other (add details above)