ci(gemfile+lock): use `ssf` customised `kitchen-docker` repo [skip ci]

* Automated using https://github.com/myii/ssf-formula/pull/294

Gemfile

@@ -7,6 +7,8 @@ source 'https://rubygems.org'
 gem 'inspec',      '~> 4.22.22'
 # Install the `kitchen-docker` gem from GitHub because the latest version
 # currently available (`2.10.0`) doesn't include a recent fix for Gentoo.
-gem 'kitchen-docker', github: 'test-kitchen/kitchen-docker', ref: '41e80fe'
+# rubocop:disable Layout/LineLength
+gem 'kitchen-docker', git: 'https://gitlab.com/saltstack-formulas/infrastructure/kitchen-docker', branch: 'ssf'
+# rubocop:enable Layout/LineLength
 gem 'kitchen-inspec', '>= 2.2.1'
 gem 'kitchen-salt', '>= 0.6.3'

Gemfile.lock

 GIT
-  remote: https://github.com/test-kitchen/kitchen-docker.git
-  revision: 41e80fed3a7cc86323e19c16a5a340cebf7e5848
-  ref: 41e80fe
+  remote: https://gitlab.com/saltstack-formulas/infrastructure/kitchen-docker
+  revision: 042e6921940a28d2502258b6a5ff3be17dd2fd37
+  branch: ssf
   specs:
     kitchen-docker (2.10.0)
       test-kitchen (>= 1.0.0)