Remove note about ephemeral_hostname

It was a hack and I don't want to document or support it long-term.  Instead call out timed_fetch as the right solution for most people.

Ent-Changes.md

@@ -7,6 +7,7 @@ HEAD
 -------------
 
 - Add API to check if a unique lock is present. See [#2932] for details.
+- Tune concurrent limiters to minimize thread thrashing under heavy contention. [#2944]
 
 1.2.1
 -------------

Pro-3.0-Upgrade.md

@@ -17,17 +17,15 @@ Sidekiq Pro 3.0 is designed to work with Sidekiq 4.0.
 * Reliable fetch has been re-implemented due to the fetch changes in
   Sidekiq 4.0.
 
-* Support for platforms without persistent hostnames.  Since reliable fetch
-  normally requires a persistent hostname, you may disable hostname usage on
-  platforms like Heroku and Docker:
+* Support for platforms without persistent hostnames.  Since the reliable\_fetch
+  algorithm requires a persistent hostname, an alternative reliability
+algorithm is now available for platforms like Heroku and Docker:
 ```ruby
 Sidekiq.configure_server do |config|
-  config.options[:ephemeral_hostname] = true
-  config.reliable_fetch!
+  config.timed_fetch!
 end
 ```
-  This option is enabled automatically if Heroku's DYNO environment variable is present.
-  Without a persistent hostname, each Sidekiq process **must** have its own unique index.
+  The wiki contains [much more detail about each reliability option](https://github.com/mperham/sidekiq/wiki/Pro-Reliability-Server).
 
 * The old 'sidekiq/notifications' features have been removed.