add workers-sdk producer section

[guybedford]

This adds a new sdk: workers-rs producers section to the WebAssembly binary created by worker-build when using workers-rs.

The benefit of this is being able to easily tell which version of Rust Workers libraries are built with when they are running on our platform.

[codspeed-hq]

Merging this PR will not alter performance

⚠️ Unknown Walltime execution environment detected

Using the Walltime instrument on standard Hosted Runners will lead to inconsistent data.

For the most accurate results, we recommend using CodSpeed Macro Runners: bare-metal machines fine-tuned for performance measurement consistency.

✅ 2 untouched benchmarks

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_{Comparing workers-sdk-producer (58550f2) with main (5d7d6d3)}