fix: link to CODE_OF_CONDUCT.md in README is busted

[beckermr]

Fixing this link.

[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.

✅ 32 untouched benchmarks

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_{Comparing beckermr-patch-2 (12c2173) with main (2f9500f)}