Improve kubernetes service specs readability

spec/models/project_services/kubernetes_service_spec.rb

@@ -203,18 +203,13 @@ describe KubernetesService, :use_clean_rails_memory_store_caching do
 
   describe '#predefined_variables' do
     let(:kubeconfig) do
-      config =
-        YAML.load(File.read(expand_fixture_path('config/kubeconfig.yml')))
-
-      config.dig('users', 0, 'user')['token'] =
-        'token'
-
+      config_file = expand_fixture_path('config/kubeconfig.yml')
+      config = YAML.load(File.read(config_file))
+      config.dig('users', 0, 'user')['token'] = 'token'
+      config.dig('contexts', 0, 'context')['namespace'] = namespace
       config.dig('clusters', 0, 'cluster')['certificate-authority-data'] =
         Base64.encode64('CA PEM DATA')
 
-      config.dig('contexts', 0, 'context')['namespace'] =
-        namespace
-
       YAML.dump(config)
     end