Update to use contract_requiring_verification_published webhook

[YOU54F]

As per this issue

https://github.com/pactflow/example-provider/issues/28

All repos should utilise

• publishing pacts with branches
• verifying pacts with branch
• utilise the contract_requiring_verification_published webhook

https://github.com/pactflow/example-provider/pull/29 https://github.com/pactflow/example-consumer/pull/105

previously this wasn't possible, as pact-net 3.x and below did not support setting the branch property and the supporting pull request was closed, https://github.com/pact-foundation/pact-net/issues/336

This means users wanting to utilise the new contract_requiring_verification_published webhook 🚀

https://docs.pact.io/blog/2021/10/11/contract-requiring-verification-published-webhook-event

[YOU54F]

Completed by

https://github.com/pactflow/example-provider-dotnet/commit/c343207f62b478bc6b681791fc69f0a54e2a5fc3

workflow in provider, which is triggered when a pact that requires verification is published

https://github.com/pactflow/example-provider-dotnet/actions/workflows/contract_requiring_verification_published.yml