Feat/v2

[YOU54F]

Use pact-ruby v2 rewrite which uses the pact-ruby-ffi gem & pact rust core to

• Generate V2 pacts (V4 is supported, but V2 chosen to test compat with pact ruby core)

Tested via Pact Broker

pact-foundation/pact_broker#843

• pact-ruby-v2 can verify v2 pacts generated by pact-rust & pact-ruby-v1
• pact-ruby-v1 can verify v2 pacts generated by pact-rust & pact-ruby-v1