Adding support for otp codes automatically

[seanmarpo]

What's Changed?

• Added a new field in GithubCredentials to support the OTP code
• Added a new config line for your Github TOTP seed - Can generate codes from here
• Added a new CLI argument --otp-code to supply your 2FA code on program run
• Pulled in a new dependency /~https://github.com/pquerna/otp to handle TOTP generation
• Updated docs to reflect changes to config.yml and the new CLI argument

Testing

I recommend creating a throwaway Github account in order to test this easier (otherwise you will need to redo your 2FA setup on your account to grab the TOTP Seed value). An image of where to click during the 2FA setup process is included below that lets you grab the raw TOTP seed value.

Update your config.yml with the new github_totp_seed field.
Run: echo "test.com" | ./git-hound

Comment out the new field in config.yml
Run: echo "test.com" | ./git-hound --otp-code <code>

Comment out the new field in config.yml
Run: echo "test.com | ./git-hound -- Ensure you are prompted for 2FA Code

Why?

I was getting annoyed while using this and having to manually enter my 2FA code every time. This allows the user to have some flexibility with automatically generating a TOTP code or letting them supply it in the CLI. Worst case, they are just prompted for it.

Feel free to adjust things as needed.

[tillson]

This is a great idea. Thank you for your contribution!