fastlane: Can't upload to itunesconnect test flight beta when password contains special characters

Original issue by @mattdelves - Imported from fastlane/deliver#312

When trying to upload an ipa to test flight beta, I’m seeing that the initial connection is successful but then when it tries to use transporter, it fails to authenticate. I solved this by changing my password to something that doesn’t contain special characters.

Output from first login

[23:34:27]: Logging into iTunesConnect
[23:34:47]: Successfully logged into iTunesConnect
[23:34:47]: Logging into iTunesConnect
[23:34:52]: Uploading ipa file to iTunesConnect
[23:34:54]: Going to upload updated app to iTunesConnect
[23:34:54]: This might take a few minutes, please don't interrupt the script

Output from failed login

[23:35:05]: [Transporter]: DBG-X: Apple's web service operation return value:
[23:35:05]: [Transporter]: DBG-X:   parameter ErrorMessage = Your Apple ID or password was entered incorrectly. (-20101)
[23:35:05]: [Transporter]: DBG-X:   parameter Errors = [Your Apple ID or password was entered incorrectly. (-20101)]
[23:35:05]: [Transporter]: DBG-X:   parameter ErrorCode = -20101
[23:35:05]: [Transporter]: DBG-X:   parameter Success = false
[23:35:05]: [Transporter Error Output]: Your Apple ID or password was entered incorrectly. (-20101)
It seems like the username or password for the account 'xxxxxxxxx' is wrong.
Please open the Keychain app, switch to `Passwords` and search for `deliver.`
You can then either remove the outdated entry or directly update it.
[23:35:05]: [Transporter]: DBG-X: The error code is: -20101
[23:35:05]: Transporter transfer failed.
[23:35:05]: 
[23:35:05]: Your Apple ID or password was entered incorrectly. (-20101)
[23:35:05]: Return status of iTunes Transporter was 1: Your Apple ID or password was entered incorrectly. (-20101)
[23:35:05]: Your Apple ID or password was entered incorrectly. (-20101)
Return status of iTunes Transporter was 1: Your Apple ID or password was entered incorrectly. (-20101)

Thanks.