Update Security Audit workflow

[tvpeter]

Describe the bug

The audit workflow failed as the pinned hash 'rustsec/audit-check@69366f33c96575abad1ee0dba8212ae3e3c0d700' cannot be found

To Reproduce

Fork and run the audit workflow

Expected behavior

For the audit workflow to pass

Build environment

• BDK-RPC-CLIENT tag/commit: 89aa6f0
• Rust/Cargo version: 1.75.0