Update docs for Shell and Workhorse communication

in full component architecture diagram

Shell communicates with Rails via Workhorse on 13.4 and later:

https://gitlab.com/gitlab-org/omnibus-gitlab/-/merge_requests/4498Signed-off-by: Takuya Noguchi <takninnovationresearch@gmail.com>

doc/development/architecture.md

@@ -151,7 +151,7 @@ graph LR
         NGINX -- TCP 8150 --> GitLabKas
         NGINX --> Registry
         %% inbound from GitLabShell
-        GitLabShell --TCP 8080 -->Puma
+        GitLabShell --> GitLabWorkhorse
 
         %% services
         Puma["Puma (GitLab Rails)"]