Swift: Add link / reference to CryptoSwift.

Author: geoffw0

swift/ql/src/queries/Security/CWE-328/WeakPasswordHashing.qhelp

@@ -82,6 +82,9 @@
                 Cheat Sheet
             </a>
         </li>
+        <li>
+            GitHub: <a href="https://github.com/krzyzanowskim/CryptoSwift/blob/main/README.md#password-based-key-derivation-function">CryptoSwift README - Password-Based Key Derivation Function</a>
+        </li>
         <li>
             libsodium: <a href="https://doc.libsodium.org/bindings_for_other_languages#bindings-programming-languages">libsodium bindings for other languages</a>
         </li>