chore: Update uvu and resolve vulnerabilities

[webJose]

This PR updates the uvu test package to its latest version, and resolves 3 vulnerabilities (via npm audit fix):

brace-expansion  1.0.0 - 1.1.11
brace-expansion Regular Expression Denial of Service vulnerability - https://github.com/advisories/GHSA-v6h2-p8h4-qcjw
fix available via `npm audit fix`
node_modules/brace-expansion

cross-spawn  7.0.0 - 7.0.4
Severity: high
Regular Expression Denial of Service (ReDoS) in cross-spawn - https://github.com/advisories/GHSA-3xgq-45jj-v275
fix available via `npm audit fix`
node_modules/cross-spawn

semver  7.0.0 - 7.5.1
Severity: high
semver vulnerable to Regular Expression Denial of Service - https://github.com/advisories/GHSA-c2qf-rxjj-qqgw
fix available via `npm audit fix`

Test script is running fine.

Note

Consider dropping uvu as it seems abandoned, and instead moving to a more modern testing framework.

Thanks for Svelte, guys! It is KING.