[deploy] Enable Puma's nakayoshi_fork feature (#11121)

* Run GC.compact before fork

* Change to nakayoshi_fork

config/puma.rb

@@ -26,6 +26,10 @@ pidfile ENV.fetch("PIDFILE") { "tmp/pids/server.pid" }
 #
 workers ENV.fetch("WEB_CONCURRENCY", 2)
 
+# calls GC a handful of times and compacts the heap on Ruby 2.7+ before forking.
+# This may reduce memory usage of Puma on MRI.
+nakayoshi_fork
+
 # Use the `preload_app!` method when specifying a `workers` number.
 # This directive tells Puma to first boot the application and load code
 # before forking the application. This takes advantage of Copy On Write