Missing setting 'dependency_proxy' in gitlab/config/gitlab.yml

The following discussion from gitlab!33662 (merged) should be addressed:

Need to add support for dependency_proxy setting in GDK:

• @ashmckenzie started a discussion: (+2 comments)

  Hmm, am still seeing some failures locally:

  $ FOSS_ONLY=1 bundle exec  rspec './spec/lib/gitlab/usage_data_spec.rb'
  
  ................F........................................F.........................
  
  Failures:
  
    1) Gitlab::UsageData when usage usage_ping_batch_counter is true behaves like usage data execution when not relying on database records #features_usage_data_ce gathers feature usage data
       Failure/Error: expect(subject[:dependency_proxy_enabled]).to eq(Gitlab.config.dependency_proxy.enabled)
  
       Settingslogic::MissingSetting:
         Missing setting 'dependency_proxy' in /Users/ash/src/gdk/gdk-primary/gitlab/config/gitlab.yml
       Shared Example Group: "usage data execution" called from ./spec/lib/gitlab/usage_data_spec.rb:568
       # ./spec/lib/gitlab/usage_data_spec.rb:224:in `block (5 levels) in <top (required)>'
       # ./spec/spec_helper.rb:308:in `block (3 levels) in <top (required)>'
       # ./spec/support/sidekiq_middleware.rb:9:in `with_sidekiq_server_middleware'
       # ./spec/spec_helper.rb:299:in `block (2 levels) in <top (required)>'
       # ./spec/spec_helper.rb:295:in `block (3 levels) in <top (required)>'
       # ./spec/spec_helper.rb:295:in `block (2 levels) in <top (required)>'
  
    2) Gitlab::UsageData when usage usage_ping_batch_counter is false behaves like usage data execution when not relying on database records #features_usage_data_ce gathers feature usage data
       Failure/Error: expect(subject[:dependency_proxy_enabled]).to eq(Gitlab.config.dependency_proxy.enabled)
  
       Settingslogic::MissingSetting:
         Missing setting 'dependency_proxy' in /Users/ash/src/gdk/gdk-primary/gitlab/config/gitlab.yml
       Shared Example Group: "usage data execution" called from ./spec/lib/gitlab/usage_data_spec.rb:576
       # ./spec/lib/gitlab/usage_data_spec.rb:224:in `block (5 levels) in <top (required)>'
       # ./spec/spec_helper.rb:308:in `block (3 levels) in <top (required)>'
       # ./spec/support/sidekiq_middleware.rb:9:in `with_sidekiq_server_middleware'
       # ./spec/spec_helper.rb:299:in `block (2 levels) in <top (required)>'
       # ./spec/spec_helper.rb:295:in `block (3 levels) in <top (required)>'
       # ./spec/spec_helper.rb:295:in `block (2 levels) in <top (required)>'
  
  Finished in 2 minutes 13.4 seconds (files took 1 minute 26.18 seconds to load)
  83 examples, 2 failures
  
  Failed examples:
  
  rspec './spec/lib/gitlab/usage_data_spec.rb[1:1:1:5:1:1]' # Gitlab::UsageData when usage usage_ping_batch_counter is true behaves like usage data execution when not relying on database records #features_usage_data_ce gathers feature usage data
  rspec './spec/lib/gitlab/usage_data_spec.rb[1:2:1:5:1:1]' # Gitlab::UsageData when usage usage_ping_batch_counter is false behaves like usage data execution when not relying on database records #features_usage_data_ce gathers feature usage data