Add vendor to scanner entity in Vulnerability Findings API

ee/app/serializers/vulnerabilities/scanner_entity.rb

@@ -3,4 +3,5 @@
 class Vulnerabilities::ScannerEntity < Grape::Entity
   expose :external_id
   expose :name
+  expose :vendor
 end

ee/changelogs/unreleased/210327-add-vendor-to-occurrences-rest-api.yml

+---
+title: Expose Vendor in Scanner in Vulnerability Findings API
+merge_request: 36184
+author:
+type: added

ee/spec/serializers/vulnerabilities/scanner_entity_spec.rb

@@ -13,7 +13,7 @@ RSpec.describe Vulnerabilities::ScannerEntity do
     subject { entity.as_json }
 
     it 'contains required fields' do
-      expect(subject).to include(:name, :external_id)
+      expect(subject).to include(:name, :external_id, :vendor)
     end
   end
 end