Support matching branch/tag targeting for contract_requiring_verification_published webhook events

[bethesque]

The contract_requiring_verification_published webhook triggers a build of the provider's main branch, and any deployed versions. The "provider version selectors" (effectively, { mainBranch: true}, { deployedOrReleased: true}) are hardcoded at this stage. It would be good to allow targeting of a provider version branch (or tag) so that the "matching feature" branches workflow can be easily achieved.

Eg.

• consumer makes a branch feat/x
• publishes pact, main+deployed versions are verified
• provider makes branch feat/x, verifies { mainBranch: true}, { matchingBranch: true } and so verifies feat/x pact
• consumer makes a change to the feat/x pact
• webhook should be able to trigger the feat/x branch of the provider.

Also, the provider may wish to target another branch as well as the main+deployed+released.

[SamJongenelen]

+1 from me