feat(api) report plugin versions on server (#8810)

* feat(api) report plugin versions on server
* add changelog entry
* update to object containing version: this allows for easier extension later, without breaking changes

CHANGELOG.md

@@ -85,6 +85,9 @@
   when updating to Kong 3.0.
 - Insert and update operations on duplicated target entities returns 409.
   [#8179](https://github.com/Kong/kong/pull/8179)
+- The list of reported plugins available on the server now returns a table of
+  metadata per plugin instead of a boolean `true`.
+  [#8810](https://github.com/Kong/kong/pull/8810)
 
 #### PDK
 

kong/api/routes/kong.lua

@@ -91,18 +91,25 @@ return {
         ngx.log(ngx.ERR, "could not get node id: ", err)
       end
 
+      local available_plugins = {}
+      for name in pairs(singletons.configuration.loaded_plugins) do
+        available_plugins[name] = {
+          version = kong.db.plugins.handlers[name].VERSION or true
+        }
+      end
+
       return kong.response.exit(200, {
         tagline = tagline,
         version = version,
         hostname = knode.get_hostname(),
         node_id = node_id,
         timers = {
           running = ngx.timer.running_count(),
-          pending = ngx.timer.pending_count()
+          pending = ngx.timer.pending_count(),
         },
         plugins = {
-          available_on_server = singletons.configuration.loaded_plugins,
-          enabled_in_cluster = distinct_plugins
+          available_on_server = available_plugins,
+          enabled_in_cluster = distinct_plugins,
         },
         lua_version = lua_version,
         configuration = conf_loader.remove_sensitive(singletons.configuration),