Authentication with steam via https://steamcommunity.com website.

Basic authentication

session := steamweb.NewSession()
response, err := session.Login(&steamweb.NewCredentials("login","password","steamid64"))
//Error checking
if response.LoginComplete {
    //We are logged in :>
}

With steamguard enabled you have to extract steamMachineAuth cookie. Chrome:

1. Go to https://steamcommunity.com
2. Click F12 to open developer console
3. Click Resources and go to cookies/steamcommunity.com
4. Look for steamMachineAuth and copy value
5. Supply the value to Credentials.Token credentials.Token="tokengoeshere"