SWAIG: Fix fastify vulnerability

[iAmmar7]

Description

Fix the fastify vulnerability under the SWAIG package.

ref: https://github.com/signalwire/signalwire-js/security/dependabot/60

Type of change

• [x] Internal refactoring
• [ ] Bug fix (bugfix - non-breaking)
• [ ] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to not work as expected)

Code snippets

In case of new feature or breaking changes, please include code snippets.