Improve the `update_schemastore` script

[AlexWaygood]

Summary

• Update the script so that it works over https
• Use a shallow clone so that it doesn't take so long

Test Plan

Before these changes, the script failed for me. Now, it works: https://github.com/SchemaStore/schemastore/pull/3772.

[github-actions[bot]]

ruff-ecosystem results

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