Bump pact from 1.19.2 to 1.20.0
Bump pact from 1.19.2 to 1.20.0

Bumps [pact](https://github.com/realestate-com-au/pact) from 1.19.2 to 1.20.0.
- [Commits](https://github.com/realestate-com-au/pact/commits)
alphagov/content-store,alphagov/content-store