Fix pact decoding by removing erroneous field.

[alexjamesmacpherson]

• Updated scalaPactDecoder and halIndexDecoder to delete the pb:consumer-versions field from the _links object when decoding a pact JSON.
• This array-type field has only recently been added to the broker and causes decoding errors due to it being an array and thus not an expected value in the Links type.
• A better solution would be to update the Links type to properly support array-type links, but i unfortunately do not have the time to fix this at present. This is however a critical blocker for ours (and others') pact verification pipelines so is critical to resolve quickly even if a better solution follows later.
• This is a rough and ready solution for #231
• More info can be found in this thread on the Pact foundation Slack channel: https://pact-foundation.slack.com/archives/CLS16AVEE/p1635324284042200

[alexjamesmacpherson]

@jbwheatley please review when you get a moment! appreciate this isn't the perfect solution, but currently scala-pact does not work with pactflow, so this will unblock anyone using the library until a better solution can be implemented