spec: remove unused pact rake task

Remove unused rake task for publishing generic api consumer pact file.
We use the script bin/contracts_publish_api instead.

Change-Id: I507b35e1aef7df201309f09f171a8e816218c7d7
Reviewed-on: https://gerrit.instructure.com/158764
Reviewed-by: Anju Reddy <areddy@instructure.com>
Reviewed-by: Rohan Cheeniyil <rcheeniyil@instructure.com>
Tested-by: Jenkins
Product-Review: Robert Lamb <rlamb@instructure.com>
QA-Review: Robert Lamb <rlamb@instructure.com>

lib/tasks/canvas_pact.rake

@@ -1,39 +0,0 @@
-if Gem.loaded_specs.has_key?('pact_broker-client')
-  require 'pact_broker/client/tasks'
-
-  # see https://github.com/pact-foundation/pact_broker-client/blob/master/README.md
-  namespace :broker do
-    GENERIC_CONSUMER_VERSION = '0.15'
-
-    PactBroker::Client::PublicationTask.new(:local) do |task|
-      format_rake_task(
-          task,
-          'http://pact-broker.docker',
-          'pact',
-          'broker',
-          'local'
-      )
-    end
-
-    PactBroker::Client::PublicationTask.new(:jenkins_post_merge) do |task|
-      format_rake_task(
-          task,
-          ENV.fetch('PACT_BROKER_HOST'),
-          ENV.fetch('PACT_BROKER_USERNAME'),
-          ENV.fetch('PACT_BROKER_PASSWORD'),
-          `git rev-parse --abbrev-ref HEAD`.strip
-      )
-    end
-
-    def format_rake_task(task, url, username, password, task_tag)
-      task.consumer_version = GENERIC_CONSUMER_VERSION
-      task.pattern = 'pacts/*.json'
-
-      task.pact_broker_base_url = url
-      task.pact_broker_basic_auth = { username: username, password: password }
-
-      task.tag = task_tag
-      puts "Pact file tagged with: #{task.tag}"
-    end
-  end
-end