[bundler/bundler] Remove `cache_command_is_package` feature flag

So that we handle the removal of `bundle cache` just like we'll handle
the removal of `bundle show` and `bundle console`.

https://github.com/bundler/bundler/commit/ff1a669efb

lib/bundler/cli.rb

@@ -69,7 +69,7 @@ module Bundler
       Bundler.ui.info "\n"
 
       primary_commands = ["install", "update",
-                          Bundler.feature_flag.cache_command_is_package? ? "cache" : "package",
+                          Bundler.feature_flag.bundler_3_mode? ? "cache" : "package",
                           "exec", "config", "help"]
 
       list = self.class.printable_commands(true)
@@ -410,7 +410,7 @@ module Bundler
       Outdated.new(options, gems).run
     end
 
-    if Bundler.feature_flag.cache_command_is_package?
+    if Bundler.feature_flag.bundler_3_mode?
       map %w[cache] => :package
     else
       desc "cache [OPTIONS]", "Cache all the gems to vendor/cache", :hide => true
@@ -424,7 +424,7 @@ module Bundler
       end
     end
 
-    desc "#{Bundler.feature_flag.cache_command_is_package? ? :cache : :package} [OPTIONS]", "Locks and then caches all of the gems into vendor/cache"
+    desc "#{Bundler.feature_flag.bundler_3_mode? ? :cache : :package} [OPTIONS]", "Locks and then caches all of the gems into vendor/cache"
     method_option "all",  :type => :boolean,
                           :default => Bundler.feature_flag.cache_all?,
                           :banner => "Include all sources (including path and git)."

lib/bundler/cli/package.rb

@@ -34,7 +34,7 @@ module Bundler
     end
 
     def setup_cache_all
-      all = options.fetch(:all, Bundler.feature_flag.cache_command_is_package? || nil)
+      all = options.fetch(:all, Bundler.feature_flag.bundler_3_mode? || nil)
 
       Bundler.settings.set_command_option_if_given :cache_all, all
 

lib/bundler/feature_flag.rb

@@ -32,7 +32,6 @@ module Bundler
     settings_flag(:auto_clean_without_path) { bundler_3_mode? }
     settings_flag(:auto_config_jobs) { bundler_3_mode? }
     settings_flag(:cache_all) { bundler_3_mode? }
-    settings_flag(:cache_command_is_package) { bundler_3_mode? }
     settings_flag(:default_install_uses_path) { bundler_3_mode? }
     settings_flag(:deployment_means_frozen) { bundler_3_mode? }
     settings_flag(:disable_multisource) { bundler_3_mode? }

lib/bundler/settings.rb

@@ -17,7 +17,6 @@ module Bundler
       auto_config_jobs
       cache_all
       cache_all_platforms
-      cache_command_is_package
       default_install_uses_path
       deployment
       deployment_means_frozen

spec/bundler/other/cli_dispatch_spec.rb

@@ -17,13 +17,4 @@ RSpec.describe "bundle command names" do
     bundle "in"
     expect(err).to eq("Ambiguous command in matches [info, init, inject, install]")
   end
-
-  context "when cache_command_is_package is set" do
-    before { bundle! "config set cache_command_is_package true" }
-
-    it "dispatches `bundle cache` to the package command" do
-      bundle "cache --verbose"
-      expect(out).to start_with "Running `bundle package --verbose`"
-    end
-  end
 end

spec/bundler/quality_spec.rb

@@ -162,7 +162,6 @@ RSpec.describe "The library itself" do
   it "documents all used settings" do
     exemptions = %w[
       auto_config_jobs
-      cache_command_is_package
       deployment_means_frozen
       forget_cli_options
       gem.coc