update from insecure version of rails

require by bundle audit for deployment
Ran transpec

Summary:

1289 conversions
  from: obj.should
    to: expect(obj).to
922 conversions
  from: == expected
    to: eq(expected)
350 conversions
  from: obj.stub(:message)
    to: allow(obj).to receive(:message)
103 conversions
  from: obj.should_not
    to: expect(obj).not_to
65 conversions
  from: obj.should_receive(:message)
    to: expect(obj).to receive(:message)
43 conversions
  from: =~ /pattern/
    to: match(/pattern/)
36 conversions
  from: obj.should_not_receive(:message)
    to: expect(obj).not_to receive(:message)
25 conversions
  from: describe 'some model' { }
    to: describe 'some model', :type => :model { }
20 conversions
  from: obj.stub_chain(:message1, :message2)
    to: allow(obj).to receive_message_chain(:message1, :message2)
18 conversions
  from: be_true
    to: be_truthy
16 conversions
  from: be_false
    to: be_falsey
6 conversions
  from: describe 'some controller' { }
    to: describe 'some controller', :type => :controller { }
5 conversions
  from: describe 'some feature' { }
    to: describe 'some feature', :type => :feature { }
5 conversions
  from: obj.stub(:message => value)
    to: allow(obj).to receive_messages(:message => value)
3 conversions
  from: > expected
    to: be > expected
3 conversions
  from: expect(collection).to have(n).items
    to: expect(collection.size).to eq(n)
2 conversions
  from: Klass.any_instance.stub(:message)
    to: allow_any_instance_of(Klass).to receive(:message)
2 conversions
  from: describe 'some helper' { }
    to: describe 'some helper', :type => :helper { }
1 conversion
  from: describe 'some mailer' { }
    to: describe 'some mailer', :type => :mailer { }
1 conversion
  from: lambda { }.should_not
    to: expect { }.not_to

2915 conversions, 1 incomplete, 17 warnings, 0 errors

I think these are ok.
WARNINGS:

The `=~ @edit_path_regex` has been converted but it might possibly be
incorrect due to a lack of runtime information. It's recommended to review the change carefully.
spec/features/collection_create_spec.rb:34:    current_path.should =~ @edit_path_regex

The `=~ exp` has been converted but it might possibly be incorrect due
to a lack of runtime information. It's recommended to review the change carefully.
spec/features/collection_create_spec.rb:81:      e.text.should =~ exp

The `=~ @edit_path_regex` has been converted but it might possibly be
incorrect due to a lack of runtime information. It's recommended to review the change carefully.
spec/features/collection_create_spec.rb:98:    current_path.should =~ @edit_path_regex

The `=~ exp` has been converted but it might possibly be incorrect due
to a lack of runtime information. It's recommended to review the change carefully.
spec/features/collection_create_spec.rb:209:    es[0...exp.size].zip(exp).each { |e, exp| e.text.should =~ exp  }

The `=~ @edit_path_regex` has been converted but it might possibly be
incorrect due to a lack of runtime information. It's recommended to review the change carefully.
spec/features/item_create_spec.rb:52:        current_path.should =~ @edit_path_regex

The `=~ @edit_path_regex` has been converted but it might possibly be
incorrect due to a lack of runtime information. It's recommended to review the change carefully.
spec/features/item_create_spec.rb:61:        current_path.should =~ @edit_path_regex

The `=~ @edit_path_regex` has been converted but it might possibly be
incorrect due to a lack of runtime information. It's recommended to review the change carefully.
spec/features/item_create_spec.rb:70:    current_path.should =~ @edit_path_regex

The `=~ exp` has been converted but it might possibly be incorrect due
to a lack of runtime information. It's recommended to review the change carefully.
spec/features/item_create_spec.rb:103:      e.text.should =~ exp

The `=~ @edit_path_regex` has been converted but it might possibly be
incorrect due to a lack of runtime information. It's recommended to review the change carefully.
spec/features/item_create_spec.rb:113:    current_path.should =~ @edit_path_regex

The `=~ @edit_path_regex` has been converted but it might possibly be
incorrect due to a lack of runtime information. It's recommended to review the change carefully.
spec/features/item_create_spec.rb:137:    current_path.should =~ @edit_path_regex

The `=~ @edit_path_regex` has been converted but it might possibly be
incorrect due to a lack of runtime information. It's recommended to review the change carefully.
spec/features/item_create_spec.rb:181:    current_path.should =~ @edit_path_regex

The `=~ exp` has been converted but it might possibly be incorrect due
to a lack of runtime information. It's recommended to review the change carefully.
spec/features/item_create_spec.rb:370:    es[0...exp.size].zip(exp).each{ |e, exp| e.text.should =~ exp  }

The `=~ @edit_path_regex` has been converted but it might possibly be
incorrect due to a lack of runtime information. It's recommended to review the change carefully.
spec/features/item_create_spec.rb:394:    current_path.should =~ @edit_path_regex

The `=~ exp` has been converted but it might possibly be incorrect due
to a lack of runtime information. It's recommended to review the change carefully.
spec/features/item_create_spec.rb:489:    es[0...exp.size].zip(exp).each{ |e, exp| e.text.should =~ exp  }

The `have(1).item` has been converted but it might possibly be incorrect
due to a lack of runtime information. It's recommended to review the change carefully.
spec/features/models/collection_spec.rb:35:expect(coll.events.event.val).to have(1).item

Cannot convert #stub into #allow since #allow is not available in the context.
spec/features/models/item_spec.rb:85: Dor::WorkflowDs.any_instance.stub(:current_priority).and_return 0

The `have(1).item` has been converted but it might possibly be incorrect
due to a lack of runtime information. It's recommended to review the change carefully.
spec/features/models/item_spec.rb:112:   expect(item.events.event.val).to have(1).item

The `=~ rgx` has been converted but it might possibly be incorrect due
to a lack of runtime information. It's recommended to review the change carefully.
spec/spec_helper.rb:201:  current_path.should =~ rgx