Update .gitmodules

[jccampagne]

Fixes #989

use url = https://github.com/... pattern

[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 jccampagne:fix-cargo-generate (7d15db8) with main (7ad7139)}