fix(deps): unpin Rsbuild to allow automatic patch upgrade

[chenjiahan]

Summary

Rsbuild follows semver and it is safe to unpin Rsbuild to allow automatic patch upgrade.

I use ~ instead of ^ because the Rspack minor releases may contain SWC breaking changes.

Checklist

• Tests updated (or not required).
• Documentation updated (or not required).

[netlify]

✅ Deploy Preview for rslib ready!

Name	Link
🔨 Latest commit	d112ec0
🔍 Latest deploy log	https://app.netlify.com/sites/rslib/deploys/670dd0f359234a000885c842
😎 Deploy Preview	https://deploy-preview-290--rslib.netlify.app
📱 Preview on mobile	Toggle QR Code... Use your smartphone camera to open QR code link.

---

To edit notification comments on pull requests, go to your Netlify site configuration.

[codspeed-hq]

CodSpeed Performance Report

Merging #290 will degrade performances by 51.98%

_{Comparing unpin_rsbuild_1014 (d112ec0) with main (86f16f9)}

Summary

❌ 1 regressions
✅ 2 untouched benchmarks

⚠️ Please fix the performance issues or acknowledge them on CodSpeed.

Benchmarks breakdown

	Benchmark	main	unpin_rsbuild_1014	Change
❌	examples/react-component-bundle-false	173.8 ms	362 ms	-51.98%