message: Fix expectation of redirect error to match ES6/7
  which now uses includes() instead of indexOf()
diff: @@ -51,7 +51,7 @@ describe('/redirect', () => {
  .expect('header', 'content-type', /text\/html/)
  .expect('bodyContains', '<h1>Juice Shop (Express ~')
  .expect('bodyContains', 'TypeError')
  - .expect('bodyContains', '&#39;indexOf&#39; of undefined')
  + .expect('bodyContains', '&#39;includes&#39; of undefined')
  .done(done)
  })
  @@ -61,7 +61,7 @@ describe('/redirect', () => {
  .expect('header', 'content-type', /text\/html/)
  .expect('bodyContains', '<h1>Juice Shop (Express ~')
  .expect('bodyContains', 'TypeError')
  - .expect('bodyContains', '&#39;indexOf&#39; of undefined')
  + .expect('bodyContains', '&#39;includes&#39; of undefined')
  .done(done)
  })
  