feat: Support verify with branch

[B3nnyL]

Issue:

#267

Context:

• Support verify with a provider branch
• Updated readme

Actual verification

broken url

[mefellows]

😆 did this tip us over the edge?

[elliottmurray]

I haven't tested this but in terms of adding a param to the ruby engine this seems legit. I can test early next week and get a release done. To Matt's point do we know why it has bumped to 15? Quite a jump. Assume it's the extra param?

[B3nnyL]

Yes, the extra parameter breaks complexity rules, same in #300

[YOU54F]

we can drop it to 12

./pact/verify_wrapper.py:136:5: C901 'VerifyWrapper.call_verify' is too complex (11)
./pact/broker.py:51:5: C901 'Broker.publish' is too complex (12)

[YOU54F]

Tested this out locally and looks good to me, nice work @B3nnyL

import unittest
from pact import Verifier


# PACT_BROKER_URL = "http://localhost"
# PACT_BROKER_USERNAME = "pactbroker"
# PACT_BROKER_PASSWORD = "pactbroker"
PACT_BROKER_URL = "https://saf.pactflow.io"
PACT_BROKER_TOKEN = "foobar"
PROVIDER_HOST = "localhost"
PROVIDER_PORT = 5001
PROVIDER_URL = f"http://{PROVIDER_HOST}:{PROVIDER_PORT}"
PROVIDER_NAME = "bar"
PROVIDER_BRANCH = 'foo'

class GetUserInfoContract(unittest.TestCase):
    def test_get_user(self):
        broker_opts = {
            # "broker_username": PACT_BROKER_USERNAME,
            # "broker_password": PACT_BROKER_PASSWORD,
            "broker_url": PACT_BROKER_URL,
            "broker_token": PACT_BROKER_TOKEN,
            "publish_version": "3",
            "publish_verification_results": True,
        }
        verifier = Verifier(provider=PROVIDER_NAME,
                            provider_base_url=PROVIDER_URL)
        success, logs = verifier.verify_with_broker(
            **broker_opts,
            verbose=True,
            provider_version_branch=PROVIDER_BRANCH,
            enable_pending=True,
        )
        print(success)
        print(logs)
        assert success == 0