What does this implement/fix? Explain your changes.

Warehouse now uses the project_urls provided to display links in the sidebar on this screen, as well as including them in API responses to help the automation tool find the source code for Requests.

Example: pypi.org/pypi/requests/json
Docs: packaging.python.org/en/latest/guides/distributing-packages-using-setuptools/#project-urls

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Does this close any currently open issues?

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Any other comments?

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Checklist

Check all those that are applicable and complete.

• Make sure to include one or more tests for your change
• If an enhancement PR, please create docs and at best an example
• Ensure you have signed the .NET Foundation CLA
• Add yourself to AUTHORS
• Updated the CHANGELOG