Logging in with SP password beginning with - breaks login

[lbergnehr]

When using the login command, e.g.

install:
  az:
    login: {}

using a service principal where the password begins with -, the constructed command will interpret the - as the beginning of a flag.

Instead of --password '-some-password-with-dash we should use --password='-some-password-with-dash.

[lbergnehr]

Would something like this make sense? getporter/porter#3326