Pact plugin driver library for Rust

Pact support library that provides an interface for interacting with Pact plugins

State of implementation

Building the Rust driver

The Rust driver is built with Cargo. The build can be run with cargo build, but there is a test DriverPactTest that requires a Protobuf plugin to work. Either skip or disable that test, or install the prototype Protobuf plugin before running the build.