Release v5.0.0.rc

Given a lot of time has passed since the last v4.x release, and there's
been many changes (including breaking ones) merged to main, let's go
with an "RC" version before doing a final release.

If we don't hear any major issues, I plan to release a final version in
a couple of weeks.

lib/devise/version.rb

@@ -1,5 +1,5 @@
 # frozen_string_literal: true
 
 module Devise
-  VERSION = "5.0.0.beta".freeze
+  VERSION = "5.0.0.rc".freeze
 end