Teach Travis CI to cache Cargo dependencies
Teach Travis CI to cache Cargo dependencies

pact-foundation/pact-reference,pact-foundation/pact-reference,pact-foundation/pact-mock-server,pact-foundation/pact-reference,pact-foundation/pact-reference,pact-foundation/pact-reference,pact-foundation/pact-reference,pact-foundation/pact-reference,pact-foundation/pact-reference