feat: add support for automatically detecting the git commit and bran…

…ch for Azure DevOps

lib/pact_broker/client/git.rb

@@ -13,7 +13,7 @@
 CI_BRANCH CI_COMMIT_ID https://documentation.codeship.com/pro/builds-and-configuration/environment-variables/
 bamboo.repository.git.branch https://confluence.atlassian.com/bamboo/bamboo-variables-289277087.html
 BITBUCKET_BRANCH BITBUCKET_COMMIT https://confluence.atlassian.com/bitbucket/variables-in-pipelines-794502608.html
-
+BUILD_SOURCEBRANCHNAME BUILD_SOURCEVERSION Azure
 =end
 
 # Keep in sync with pact-provider-verifier/lib/pact/provider_verifier/git.rb
@@ -25,8 +25,8 @@ module Git
       using PactBroker::Client::HashRefinements
 
       COMMAND = 'git rev-parse --abbrev-ref HEAD'.freeze
-      BRANCH_ENV_VAR_NAMES = %w{GITHUB_HEAD_REF GITHUB_REF BUILDKITE_BRANCH CIRCLE_BRANCH TRAVIS_BRANCH GIT_BRANCH GIT_LOCAL_BRANCH APPVEYOR_REPO_BRANCH CI_COMMIT_REF_NAME BITBUCKET_BRANCH}.freeze
-      COMMIT_ENV_VAR_NAMES = %w{GITHUB_SHA BUILDKITE_COMMIT CIRCLE_SHA1 TRAVIS_COMMIT GIT_COMMIT APPVEYOR_REPO_COMMIT CI_COMMIT_ID BITBUCKET_COMMIT}
+      BRANCH_ENV_VAR_NAMES = %w{GITHUB_HEAD_REF GITHUB_REF BUILDKITE_BRANCH CIRCLE_BRANCH TRAVIS_BRANCH GIT_BRANCH GIT_LOCAL_BRANCH APPVEYOR_REPO_BRANCH CI_COMMIT_REF_NAME BITBUCKET_BRANCH BUILD_SOURCEBRANCHNAME}.freeze
+      COMMIT_ENV_VAR_NAMES = %w{GITHUB_SHA BUILDKITE_COMMIT CIRCLE_SHA1 TRAVIS_COMMIT GIT_COMMIT APPVEYOR_REPO_COMMIT CI_COMMIT_ID BITBUCKET_COMMIT BUILD_SOURCEVERSION}
       BUILD_URL_ENV_VAR_NAMES = %w{BUILDKITE_BUILD_URL CIRCLE_BUILD_URL TRAVIS_BUILD_WEB_URL BUILD_URL }
 
       def self.commit