Change freeze-periods.json to freeze_periods.json

spec/frontend/fixtures/freeze_period.rb

@@ -20,7 +20,7 @@ RSpec.describe 'Freeze Periods (JavaScript fixtures)' do
   describe API::FreezePeriods, '(JavaScript fixtures)', type: :request do
     include ApiHelpers
 
-    it 'api/freeze-periods/freeze-periods.json' do
+    it 'api/freeze-periods/freeze_periods.json' do
       create(:ci_freeze_period, project: project, freeze_start: '5 4 * * *', freeze_end: '5 9 * 8 *', cron_timezone: 'America/New_York')
       create(:ci_freeze_period, project: project, freeze_start: '0 12 * * 1-5', freeze_end: '0 1 5 * *', cron_timezone: 'Etc/UTC')
       create(:ci_freeze_period, project: project, freeze_start: '0 12 * * 1-5', freeze_end: '0 16 * * 6', cron_timezone: 'Europe/Berlin')