Simplify OmniAuth version check by trying to load the gem with the ne…

…cessary version

lib/devise/omniauth.rb

@@ -1,17 +1,14 @@
 # frozen_string_literal: true
 
 begin
+  gem "omniauth", ">= 1.0.0"
+
   require "omniauth"
-  require "omniauth/version"
 rescue LoadError
   warn "Could not load 'omniauth'. Please ensure you have the omniauth gem >= 1.0.0 installed and listed in your Gemfile."
   raise
 end
 
-if Gem::Version.new(OmniAuth::VERSION) < Gem::Version.new('1.0.0')
-  raise "You are using an old OmniAuth version, please ensure you have 1.0.0 version or later installed."
-end
-
 # Clean up the default path_prefix. It will be automatically set by Devise.
 OmniAuth.config.path_prefix = nil