fix: ensure configured webhook headers are used when making request

Author: bethesque

lib/pact_broker/webhooks/webhook_request_template.rb

@@ -31,6 +31,7 @@ def build(context)
         attributes = {
           method: http_method,
           url: build_url(context[:pact], context[:verification]),
+          headers: headers,
           username: username,
           password: password,
           uuid: uuid,

spec/lib/pact_broker/webhooks/webhook_request_template_spec.rb

@@ -10,7 +10,8 @@ module Webhooks
           username: "foo",
           password: "bar",
           uuid: "1234",
-          body: body
+          body: body,
+          headers: {'Foo' => 'bar'}
         }
       end
 
@@ -21,7 +22,8 @@ module Webhooks
           username: "foo",
           password: "bar",
           uuid: "1234",
-          body: built_body
+          body: built_body,
+          headers: {'Foo' => 'bar'}
         }
       end