Temporarily remove ruby from Gemfile

See 707b5cb for more details.

Author: rafaelfranca

railties/lib/rails/generators/rails/app/templates/Gemfile.tt

@@ -1,7 +1,5 @@
 source "https://rubygems.org"
 
-ruby <%= "\"#{gem_ruby_version}\"" -%>
-
 <% gemfile_entries.each do |gemfile_entry| -%>
 <%= gemfile_entry %>
 <% end -%>

railties/test/generators/app_generator_test.rb

@@ -1010,9 +1010,6 @@ def test_inclusion_of_ruby_version
 
     ruby_version = "#{Gem::Version.new(Gem::VERSION) >= Gem::Version.new("3.3.13") ? Gem.ruby_version : RUBY_VERSION}"
 
-    assert_file "Gemfile" do |content|
-      assert_match("ruby \"#{ruby_version}\"", content)
-    end
     assert_file ".devcontainer/Dockerfile" do |content|
       minor_ruby_version = ruby_version.match(/^\d+\.\d+/).to_s
       assert_match(/ARG RUBY_VERSION=#{minor_ruby_version}$/, content)