Duplicate attachments by filename are removed

[deepwell]

Adding more than 1 attachment with the same filename(s) are removed when sending with nodemailer-sendgrid-tranport. This bug does not effect other transports.

Eg: attachments

[
  { filename: 'presentation.xlsx',
    path: '/home/users/files/2f7402e1-4345-45bb-969a-e67b68c17e90.xlsx' },
  { filename: 'presentation.xlsx',
    path: '/home/users/files/0sdfhi43t-sfefio-sdfsdf-3433-33-324234lkd.xlsx' } 
]

Expectation:
Attachments should not be removed.

[deepwell]

It looks like the fix is here: https://github.com/sendgrid/sendgrid-nodejs/pull/180/files