Adds the CONTRIBUTOR SeatType

[adecounter]

Pull Request

Description

Smartsheet has added a new SeatType of CONTRIBUTOR. This new SeatType has been added for compatibility for the SDK.

Related Issue

Type of Change

• Bug fix
• New feature
• Documentation update
• Code refactoring
• Other (please describe):

Environment Information

• Smartsheet API Version: [e.g. 2.0]
• Smartsheet Python SDK Version: [e.g. 3.0.0]
• Python Version: [e.g. 3.10]

What Changes Were Made

• adds the CONTRIBUTOR SeatType
• adds tests to expand to CONTRIBUTOR SeatType
• updates details in CHANGELOG.md

Why These Changes Were Made

In support of new SeatType enum response.

Testing

Tests have been added in similar fashion to other SeatType validations specifically for the CONTRIBUTOR SeatType

Checklist

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• I have updated the relevant files in docs-source/ (see Documentation guidelines)
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes

Additional Notes

[roomote-v0]

Rooviewer   See task

Review complete. This PR cleanly adds the CONTRIBUTOR seat type to all relevant enums (SeatType, UpgradeSeatType, DowngradeSeatType) with appropriate test coverage and CHANGELOG updates. No issues found.

_{Mention @roomote in a comment to request specific changes to this pull request or fix all unresolved issues.}