Suggestion: Add another input for DevHub SFDX Auth URL and set as default devhub username

[johnforeland]

When adding a DevHub SFDX Auth URL to the input, it is not set as default devhub username by default (because that would break non-DevHub Auth URLs).

I would suggest adding another input (two in total):

• sfdx-auth-url
  • Same as today
  • Set with parameter -s (--setdefaultusername)
• devhub-sfdx-auth-url
  • Set with parameter -d (--setdefaultdevhubusername)