chore: Fix "repository" field in pkg.json

[rschristian]

Only saw when I went to publish, seems NPM prefers this form now:

npm warn publish npm auto-corrected some errors in your package.json when publishing.  Please run "npm pkg fix" to address these errors.
npm warn publish errors corrected:
npm warn publish "repository" was changed from a string to an object
npm warn publish "repository.url" was normalized to "git+https://github.com/preactjs/preset-vite.git"