Add set_role and keep_default role checks

[andrew-hai]

Description

• raise errors if set role or keep default role used in wrong migration.

Manual Test Plan

• create data change migration with set_role and run it (customer_service);

  class Test < ActiveRecord::Migration[5.2]
  include DataUpdate
  
  set_role "superhero"
  
  def up
  apply_update "populate_example_data_update"
  end
  
  def down
  revert_update "populate_example_data_update"
  end
  end

• error should be raised;

  Caused by:
  PgSaurus::UseKeepDefaultRoleError: Use keep_default_role instead of set_role for data change migration Test

• create structure change migration with keep_default_role and run it (customer_service);

  class Test < ActiveRecord::Migration[5.2]
  keep_default_role
  
  def up
  add_index :customers, :created_at
  end
  
  def down
  remove_index :customers, :created_at
  end
  end

• error should be raised.

  Caused by:
  PgSaurus::UseSetRoleError: Use set_role instead of keep_default_role for structure migration Test