Seat link to include self managed instance version

ee/app/models/gitlab/seat_link_data.rb

@@ -49,6 +49,7 @@ module Gitlab
 
     def data
       {
+        gitlab_version: Gitlab::VERSION,
         timestamp: timestamp.iso8601,
         date: timestamp.to_date.to_s,
         license_key: key,

ee/changelogs/unreleased/328465-send-version.yml

+---
+title: Sync gitlab version during seat link
+merge_request: 60362
+author:
+type: changed

ee/spec/models/gitlab/seat_link_data_spec.rb

@@ -81,6 +81,7 @@ RSpec.describe Gitlab::SeatLinkData do
     it 'returns payload data as a JSON string' do
       expect(subject.to_json).to eq(
         {
+          gitlab_version: Gitlab::VERSION,
           timestamp: timestamp.iso8601,
           date: timestamp.to_date.iso8601,
           license_key: key,

ee/spec/workers/sync_seat_link_request_worker_spec.rb

@@ -18,6 +18,7 @@ RSpec.describe SyncSeatLinkRequestWorker, type: :worker do
       expect(WebMock).to have_requested(:post, seat_link_url).with(
         headers: { 'Content-Type' => 'application/json' },
         body: {
+          gitlab_version: Gitlab::VERSION,
           timestamp: '2019-12-31T23:20:12Z',
           date: '2019-12-31',
           license_key: '123',
@@ -71,6 +72,7 @@ RSpec.describe SyncSeatLinkRequestWorker, type: :worker do
         expect(WebMock).to have_requested(:post, seat_link_url).with(
           headers: { 'Content-Type' => 'application/json' },
           body: {
+            gitlab_version: Gitlab::VERSION,
             timestamp: '2020-01-01T00:00:00Z',
             date: '2020-01-01',
             license_key: '123',