add ext-pqcrypto

[paragonie-security]

Add project

• Project name: ext-pqcrypto
• URL: https://github.com/paragonie/ext-pqcrypto
• Category: Cryptography & Security
• Description: PHP wrapper for RustCrypto's post-quantum cryptography implementations.

Checklist

• Project uses ext-php-rs as a dependency
• Entry follows the format: - [name](url) - Description.
• Entry is placed alphabetically in the correct category
• Project has a README with usage instructions

[ptondereau]

Wow awesome and thanks!