Fix typo in pyproject.toml description

[AYadrov]

Little typo that I observed today:)

[codspeed-hq]

Merging this PR will not alter performance

✅ 12 untouched benchmarks
⏩ 2 skipped benchmarks¹

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_{Comparing AYadrov:patch-1 (59b2228) with main (0c25eaf)}

Footnotes

1. 2 benchmarks were skipped, so the baseline results were used instead. If they were deleted from the codebase, click here and archive them to remove them from the performance reports. ↩

[saulshanabrook]

Thank you!