Apply manual rubocop fixes

app/services/proforma_service/convert_exercise_to_task.rb

@@ -7,6 +7,7 @@ module ProformaService
     DEFAULT_LANGUAGE = 'de'
 
     def initialize(exercise: nil)
+      super()
       @exercise = exercise
     end
 

app/services/proforma_service/convert_task_to_exercise.rb

@@ -3,6 +3,7 @@
 module ProformaService
   class ConvertTaskToExercise < ServiceBase
     def initialize(task:, user:, exercise: nil)
+      super()
       @task = task
       @user = user
       @exercise = exercise || Exercise.new(unpublished: true)

app/services/proforma_service/export_task.rb

@@ -3,6 +3,7 @@
 module ProformaService
   class ExportTask < ServiceBase
     def initialize(exercise: nil)
+      super()
       @exercise = exercise
     end
 

app/services/proforma_service/import.rb

@@ -3,6 +3,7 @@
 module ProformaService
   class Import < ServiceBase
     def initialize(zip:, user:)
+      super()
       @zip = zip
       @user = user
     end