bump sdk to 3.1.68-latest

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Built bundles:

• Postgres WASM: https://github.com/electric-sql/pglite/actions/runs/11220086089/artifacts/2025061433
• Interim build files: https://github.com/electric-sql/pglite/actions/runs/11220086089/artifacts/2025061514
• PGlite: https://github.com/electric-sql/pglite/actions/runs/11220086089/artifacts/2025091201
• Demos: https://github.com/electric-sql/pglite/actions/runs/11220086089/artifacts/2025105249

[github-actions[bot]]

🚀 Deployed on https://670411c3633d6740c8e037cb--pglite.netlify.app